Update contrib mentions of headings after H3->H2 content migration (g…

…ithub#19884)

content/README.md

@@ -181,7 +181,7 @@ featuredLinks:
 ### `miniTocMaxHeadingLevel`
 
 - Purpose: Indicates the maximum heading level to include in an article's mini TOC. See [Autogenerated mini TOCs](#autogenerated-mini-tocs) for more info.
-- Type: `Number`. Default is `3`. Minimum is `2`. Maximum is `4`.
+- Type: `Number`. Default is `2`. Minimum is `2`. Maximum is `3`.
 - Optional.
 
 ### `allowTitleToDifferFromFilename`
@@ -275,9 +275,9 @@ As an alternative, you can change the single quotes surrounding the frontmatter
 
 ## Autogenerated mini TOCs
 
-Every article on the help site displays an autogenerated "In this article" section (aka mini TOC) at the top of the page that includes links to all `H2`s and `H3`s in the article by default.
+Every article on the help site displays an autogenerated "In this article" section (aka mini TOC) at the top of the page that includes links to all `H2`s in the article by default.
 
-* To make the mini TOC include additional (or fewer) heading levels, you can add [`miniTocMaxHeadingLevel` frontmatter](#miniTocMaxHeadingLevel) to specify the maximum heading level. For example: `miniTocMaxHeadingLevel: 4`
+* To make the mini TOC include additional (or fewer) heading levels, you can add [`miniTocMaxHeadingLevel` frontmatter](#miniTocMaxHeadingLevel) to specify the maximum heading level. For example: `miniTocMaxHeadingLevel: 3`
 * To disable the mini TOC for a specific article, you can add this frontmatter: [`showMiniToc: false`](#showMiniToc)
 
 Mini TOCs do not appear on product landing pages, category landing pages, or map topic pages.

contributing/content-model.md

@@ -164,8 +164,8 @@ Use the [referential content template](https://github.com/github/docs/blob/main/
 - For subjects with multiple elements to explain, use a table
   - Example: [Repository permission levels for an organization](https://docs.github.com/en/organizations/managing-access-to-your-organizations-repositories/repository-permission-levels-for-an-organization)
 - For longer referential content, such as YAML syntax for workflows, use headers consistently:
-  - H3 headers for each distinct section
-  - H4 headers for subsections, such as examples
+  - H2 headers for each distinct section
+  - H3 headers for subsections, such as examples
   - Example: [Workflow syntax for GitHub Actions](https://docs.github.com/en/actions/reference/workflow-syntax-for-github-actions)
 
 #### Titles for referential content

contributing/content-style-guide.md

@@ -156,7 +156,7 @@ Workflow runs are delayed when too many workflows run at once. Since many users
 
 ## Headers
 
-Use H3 for headers, and H4 for subheaders. When referring to headers, surround the header name with quotation marks.
+Use H2 for headers, and H3 for subheaders. When referring to headers, surround the header name with quotation marks.
 - **Use:** Under “User licenses”, view your total licenses.
 
 To orient readers and help them understand if the section is relevant to them, include introductory content after a header - don’t locate a subheader directly following a header.
@@ -217,7 +217,7 @@ For plain text, use linebreaks to separate paragraphs in the source (two consecu
 
 Introduce links consistently using a standard format that clearly indicates where we’re linking: "For more information, see X [or "Page/article title"] in the X documentation." Do not include quotation marks within a hyperlink.
 
-Links should be meaningful and provide high value to the user’s journey - link out carefully. Move links that are helpful but not necessary to an article’s further reading section. Do not repeat the same link more than once in the same article or under the same H3 header.
+Links should be meaningful and provide high value to the user’s journey - link out carefully. Move links that are helpful but not necessary to an article’s further reading section. Do not repeat the same link more than once in the same article or under the same H2 header.
 
 For accessibility and readability, avoid inline or midsentence links.
 - **Use:** OAuth2 tokens can be acquired programmatically for applications that are not websites. For more information, see "[Setting up and registering OAuth Apps](https://developer.github.com/apps/building-integrations/setting-up-and-registering-oauth-apps/)" and "[Create a new authorization](https://docs.github.com/en/enterprise-server@2.22/rest/reference/oauth-authorizations/#create-a-new-authorization)."