Docs: Replace Recommonmark with MyST Parser

Recommonmark has been deprecated since 2021 [1] and the last release was
over 3 years ago [2]. As per their announcement, Markedly Structured
Text (MyST) Parser [3] is the recommended replacement.

For the most part, the existing documentation is compatible with MyST,
as both parsers are built around the CommonMark flavor of Markdown. The
main difference that affects coreboot is how the Sphinx toctree is
generated. Recommonmark has a feature called auto_toc_tree, which
converts single level lists of references into a toctree:

* [Part 1: Starting from scratch](part1.md)
* [Part 2: Submitting a patch to coreboot.org](part2.md)
* [Part 3: Writing unit tests](part3.md)
* [Managing local additions](managing_local_additions.md)
* [Flashing firmware](flashing_firmware/index.md)

MyST Parser does not provide a replacement for this feature, meaning the
toctree must be defined manually. This is done using MyST's syntax for
Sphinx directives:

```{toctree}
:maxdepth: 1

Part 1: Starting from scratch <part1.md>
Part 2: Submitting a patch to coreboot.org <part2.md>
Part 3: Writing unit tests <part3.md>
Managing local additions <managing_local_additions.md>
Flashing firmware <flashing_firmware/index.md>
```

Internally, auto_toc_tree essentially converts lists of references into
the Sphinx toctree structure that the MyST syntax above more directly
represents.

The toctrees were converted to the MyST syntax using the following
command and Python script:

`find ./ -iname "*.md" | xargs -n 1 python conv_toctree.py`

```
import re
import sys

in_list = False
f = open(sys.argv[1])
lines = f.readlines()
f.close()

with open(sys.argv[1], "w") as f:
    for line in lines:
        match = re.match(r"^[-*+] \[(.*)\]\((.*)\)$", line)
        if match is not None:
            if not in_list:
                in_list = True
                f.write("```{toctree}\n")
                f.write(":maxdepth: 1\n\n")
            f.write(match.group(1) + " <" + match.group(2) + ">\n")
        else:
            if in_list:
                f.write("```\n")
            f.write(line)
            in_list = False

    if in_list:
        f.write("```\n")
```

While this does add a little more work for creating the toctree, this
does give more control over exactly what goes into the toctree. For
instance, lists of links to external resources currently end up in the
toctree, but we may want to limit it to pages within coreboot.

This change does break rendering and navigation of the documentation in
applications that can render Markdown, such as Okular, Gitiles, or the
GitHub mirror. Assuming the docs are mainly intended to be viewed after
being rendered to doc.coreboot.org, this is probably not an issue in
practice.

Another difference is that MyST natively supports Markdown tables,
whereas with Recommonmark, tables had to be written in embedded rST [4].
However, MyST also supports embedded rST, so the existing tables can be
easily converted as the syntax is nearly identical.

These were converted using
`find ./ -iname "*.md" | xargs -n 1 sed -i "s/eval_rst/{eval-rst}/"`

Makefile.sphinx and conf.py were regenerated from scratch by running
`sphinx-quickstart` using the updated version of Sphinx, which removes a
lot of old commented out boilerplate. Any relevant changes coreboot had
made on top of the previous autogenerated versions of these files were
ported over to the newly generated file.

From some initial testing the generated webpages appear and function
identically to the existing documentation built with Recommonmark.

TEST: `make -C util/docker docker-build-docs` builds the documentation
successfully and the generated output renders properly when viewed in
a web browser.

[1] https://github.com/readthedocs/recommonmark/issues/221
[2] https://pypi.org/project/recommonmark/
[3] https://myst-parser.readthedocs.io/en/latest/
[4] https://doc.coreboot.org/getting_started/writing_documentation.html

Change-Id: I0837c1722fa56d25c9441ea218e943d8f3d9b804
Signed-off-by: Nicholas Chin <nic.c3.14@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/73158
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

1 files changed, 25 insertions, 88 deletions

diff --git a/Documentation/conf.py b/Documentation/conf.py
index 143e60d4ad..b0f2975dc7 100644
--- a/Documentation/conf.py
+++ b/Documentation/conf.py
@@ -1,46 +1,34 @@
-# -*- coding: utf-8 -*-
-import subprocess
-from recommonmark.parser import CommonMarkParser
-import sphinx
-
-# Get Sphinx version
-major = 0
-minor = 0
-patchlevel = 0
-version = sphinx.__version__.split(".")
-if len(version) > 1:
-	major = int(version[0])
-	minor = int(version[1])
-	if len(version) > 2:
-		patchlevel = int(version[2])
-
-# Add any paths that contain templates here, relative to this directory.
-templates_path = ['_templates']
+# Configuration file for the Sphinx documentation builder.
+#
+# For the full list of built-in configuration values, see the documentation:
+# https://www.sphinx-doc.org/en/master/usage/configuration.html
 
-# The suffix(es) of source filenames.
-source_suffix = ['.md']
+# -- Project information -----------------------------------------------------
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#project-information
 
-# The master toctree document.
-master_doc = 'index'
+import subprocess
 
-# General information about the project.
-project = u'coreboot'
-copyright = u'CC-by 4.0 the coreboot project'
-author = u'the coreboot project'
+project = 'coreboot'
+copyright = 'CC-by 4.0 the coreboot project'
+author = 'the coreboot project'
 
-# The version info for the project you're documenting, acts as replacement for
-# |version| and |release|, also used in various other places throughout the
-# built documents.
-#
-# The full version, including alpha/beta/rc tags.
 release = subprocess.check_output(('git', 'describe')).decode("utf-8")
 # The short X.Y version.
 version = release.split("-")[0]
 
-extensions = []
-# Load recommonmark, supported since 1.8+
-if major >= 2 or (major == 1 and minor >= 8):
-    extensions += ['recommonmark']
+
+# -- General configuration ---------------------------------------------------
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#general-configuration
+
+extensions = ["myst_parser"]
+
+myst_heading_anchors = 5
+
+templates_path = ['_templates']
+exclude_patterns = ['_build', 'Thumbs.db', '.DS_Store']
+
+# The name of the Pygments (syntax highlighting) style to use.
+pygments_style = 'sphinx'
 
 # Try to load DITAA
 try:
@@ -57,62 +45,11 @@ else:
 # Usually you set "language" from the command line for these cases.
 language = 'en'
 
-# List of patterns, relative to source directory, that match files and
-# directories to ignore when looking for source files.
-# This patterns also effect to html_static_path and html_extra_path
-exclude_patterns = ['_build', 'Thumbs.db', '.DS_Store']
+# -- Options for HTML output -------------------------------------------------
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#options-for-html-output
 
-# The name of the Pygments (syntax highlighting) style to use.
-pygments_style = 'sphinx'
-
-# A list of ignored prefixes for module index sorting.
-# modindex_common_prefix = []
-
-# If true, keep warnings as "system message" paragraphs in the built documents.
-# keep_warnings = False
-
-# If true, `todo` and `todoList` produce output, else they produce nothing.
-todo_include_todos = False
-
-
-# -- Options for HTML output ----------------------------------------------
-
-# The theme to use for HTML and HTML Help pages.  See the documentation for
-# a list of builtin themes.
-#
 html_theme = 'sphinx_rtd_theme'
-
-# Add any paths that contain custom static files (such as style sheets) here,
-# relative to this directory. They are copied after the builtin static files,
-# so a file named "default.css" will overwrite the builtin "default.css".
 html_static_path = ['_static']
-
 html_css_files = [
     'theme_overrides.css',  # override wide tables in RTD theme
 ]
-
-# Output file base name for HTML help builder.
-htmlhelp_basename = 'corebootdoc'
-
-enable_auto_toc_tree = True
-
-class MyCommonMarkParser(CommonMarkParser):
-    # remove this hack once upstream RecommonMark supports inline code
-    def visit_code(self, mdnode):
-        from docutils import nodes
-        n = nodes.literal(mdnode.literal, mdnode.literal)
-        self.current_node.append(n)
-
-def setup(app):
-    from recommonmark.transform import AutoStructify
-    # Load recommonmark on old Sphinx
-    if major == 1 and minor < 8:
-        app.add_source_parser('.md', MyCommonMarkParser)
-
-    app.add_config_value('recommonmark_config', {
-        'enable_auto_toc_tree': True,
-        'enable_auto_doc_ref': False, # broken in Sphinx 1.6+
-        'enable_eval_rst': True,
-        'url_resolver': lambda url: '/' + url
-    }, True)
-    app.add_transform(AutoStructify)