Documentation: Fix header levels

This fixes the following MyST Parser warnings:

- Non-consecutive header level increase
- Document headings start at H2, not H1

The header levels (the number of "#" characters before a heading) are
intended to form a logical hierarchy of each section and subsection in a
document. A subsection typically should have a header level one more
than its parent section. Most of these warnings are caused by extra "#"
characters, which were simply removed, or sections missing a "#"
character to make it fall under its parent section.

Notable changes:

getting_started/kconfig.md: Changed the header level of the "Keywords"
section from 2 to 3 to fall under "Kconfig Language" (level 2), and
increased the level of each keyword from 3 to 4 to remain under
"Keywords". This also fixes the warnings of "H3 to H5" increases, since
the Usage/Example/Notes/Restrictions sections for each keyword had a
level of 5.

soc/intel/cse_fw_update/cse_fw_update.md: Changed the first line to a
top level header acting as the title of the document. Without this
soc/intel/index.md displays all the level 2 headers in this document
instead of a single link to cse_fw_update.md.

Change-Id: Ia1f8b52e39b7b6524bef89a95365541235b5b1b9
Signed-off-by: Nicholas Chin <nic.c3.14@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83382
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Elyes Haouas <ehaouas@noos.fr>

1 files changed, 4 insertions, 4 deletions

diff --git a/Documentation/tutorial/part1.md b/Documentation/tutorial/part1.md
index bba00d5f77..88be6fff0b 100644
--- a/Documentation/tutorial/part1.md
+++ b/Documentation/tutorial/part1.md
@@ -86,7 +86,7 @@ make -C payloads/coreinfo
 
 ### Step 5 - Configure the build
 
-##### Configure your mainboard
+#### Configure your mainboard
 
 ```Bash
 make menuconfig
@@ -104,7 +104,7 @@ select < Exit >
 These should be the default selections, so if anything else was set, run
 `make distclean` to remove your old config file and start over.
 
-##### Optionally use your system toolchain (Again, not recommended)
+#### Optionally use your system toolchain (Again, not recommended)
 
 ```Text
 select 'General Setup' menu
@@ -112,7 +112,7 @@ select 'Allow building with any toolchain'
 select < Exit >
 ```
 
-##### Select the payload
+#### Select the payload
 
 ```Text
 select 'Payload' menu
@@ -125,7 +125,7 @@ select < Exit >
 select < Yes >
 ```
 
-##### Check your configuration (optional step):
+#### Check your configuration (optional step):
 
 ```Bash
 make savedefconfig