feat(core): make broken link checker detect broken anchors - add onBrokenAnchors config (#9528)

Co-authored-by: sebastienlorber <lorber.sebastien@gmail.com>

website/docs/api/docusaurus.config.js.mdx

@@ -188,7 +188,7 @@ export default {
 
 The behavior of Docusaurus when it detects any broken link.
 
-By default, it throws an error, to ensure you never ship any broken link, but you can lower this security if needed.
+By default, it throws an error, to ensure you never ship any broken link.
 
 :::note
 
@@ -196,13 +196,21 @@ The broken links detection is only available for a production build (`docusaurus
 
 :::
 
+### `onBrokenAnchors` {#onBrokenAnchors}
+
+- Type: `'ignore' | 'log' | 'warn' | 'throw'`
+
+The behavior of Docusaurus when it detects any broken anchor declared with the `Heading` component of Docusaurus.
+
+By default, it prints a warning, to let you know about your broken anchors.
+
 ### `onBrokenMarkdownLinks` {#onBrokenMarkdownLinks}
 
 - Type: `'ignore' | 'log' | 'warn' | 'throw'`
 
 The behavior of Docusaurus when it detects any broken Markdown link.
 
-By default, it prints a warning, to let you know about your broken Markdown link, but you can change this security if needed.
+By default, it prints a warning, to let you know about your broken Markdown link.
 
 ### `onDuplicateRoutes` {#onDuplicateRoutes}
 

website/docs/api/plugins/plugin-content-docs.mdx

@@ -42,10 +42,10 @@ Accepted fields:
 | `include` | `string[]` | `['**/*.{md,mdx}']` | Array of glob patterns matching Markdown files to be built, relative to the content path. |
 | `exclude` | `string[]` | _See example configuration_ | Array of glob patterns matching Markdown files to be excluded. Serves as refinement based on the `include` option. |
 | `sidebarPath` | <code>false \| string</code> | `undefined` | Path to sidebar configuration. Use `false` to disable sidebars, or `undefined` to create a fully autogenerated sidebar. |
-| `sidebarCollapsible` | `boolean` | `true` | Whether sidebar categories are collapsible by default. See also [Collapsible categories](/docs/sidebar#collapsible-categories) |
-| `sidebarCollapsed` | `boolean` | `true` | Whether sidebar categories are collapsed by default. See also [Expanded categories by default](/docs/sidebar#expanded-categories-by-default) |
-| `sidebarItemsGenerator` | <a href="#SidebarGenerator"><code>SidebarGenerator</code></a> | _Omitted_ | Function used to replace the sidebar items of type `'autogenerated'` with real sidebar items (docs, categories, links...). See also [Customize the sidebar items generator](/docs/sidebar#customize-the-sidebar-items-generator) |
-| `numberPrefixParser` | <code>boolean \|</code> <a href="#PrefixParser"><code>PrefixParser</code></a> | _Omitted_ | Custom parsing logic to extract number prefixes from file names. Use `false` to disable this behavior and leave the docs untouched, and `true` to use the default parser. See also [Using number prefixes](/docs/sidebar#using-number-prefixes) |
+| `sidebarCollapsible` | `boolean` | `true` | Whether sidebar categories are collapsible by default. See also [Collapsible categories](/docs/sidebar/items#collapsible-categories) |
+| `sidebarCollapsed` | `boolean` | `true` | Whether sidebar categories are collapsed by default. See also [Expanded categories by default](/docs/sidebar/items#expanded-categories-by-default) |
+| `sidebarItemsGenerator` | <a href="#SidebarGenerator"><code>SidebarGenerator</code></a> | _Omitted_ | Function used to replace the sidebar items of type `'autogenerated'` with real sidebar items (docs, categories, links...). See also [Customize the sidebar items generator](/docs/sidebar/autogenerated#customize-the-sidebar-items-generator) |
+| `numberPrefixParser` | <code>boolean \|</code> <a href="#PrefixParser"><code>PrefixParser</code></a> | _Omitted_ | Custom parsing logic to extract number prefixes from file names. Use `false` to disable this behavior and leave the docs untouched, and `true` to use the default parser. See also [Using number prefixes](/docs/sidebar/autogenerated#using-number-prefixes) |
 | `docsRootComponent` | `string` | `'@theme/DocsRoot'` | Parent component of all the docs plugin pages (including all versions). Stays mounted when navigation between docs pages and versions. |
 | `docVersionRootComponent` | `string` | `'@theme/DocVersionLayout'` | Parent component of all docs pages of an individual version (doc pages with sidebars, tags pages). Stays mounted when navigation between pages of that specific version. |
 | `docRootComponent` | `string` | `'@theme/DocPage'` | Parent component of all doc pages with sidebars (regular docs pages, category generated index pages). Stays mounted when navigation between such pages. |
@@ -275,7 +275,7 @@ Accepted fields:
 | `title` | `string` | Markdown title or `id` | The text title of your document. Used for the page metadata and as a fallback value in multiple places (sidebar, next/previous buttons...). Automatically added at the top of your doc if it does not contain any Markdown title. |
 | `pagination_label` | `string` | `sidebar_label` or `title` | The text used in the document next/previous buttons for this document. |
 | `sidebar_label` | `string` | `title` | The text shown in the document sidebar for this document. |
-| `sidebar_position` | `number` | Default ordering | Controls the position of a doc inside the generated sidebar slice when using `autogenerated` sidebar items. See also [Autogenerated sidebar metadata](/docs/sidebar#autogenerated-sidebar-metadata). |
+| `sidebar_position` | `number` | Default ordering | Controls the position of a doc inside the generated sidebar slice when using `autogenerated` sidebar items. See also [Autogenerated sidebar metadata](/docs/sidebar/autogenerated#autogenerated-sidebar-metadata). |
 | `sidebar_class_name` | `string` | `undefined` | Gives the corresponding sidebar label a special class name when using autogenerated sidebars. |
 | `sidebar_custom_props` | `object` | `undefined` | Assign [custom props](../../guides/docs/sidebar/index.mdx#passing-custom-props) to the sidebar item referencing this doc |
 | `displayed_sidebar` | `string` | `undefined` | Force the display of a given sidebar when browsing the current document. Read the [multiple sidebars guide](../../guides/docs/sidebar/multiple-sidebars.mdx) for details. |
@@ -285,7 +285,7 @@ Accepted fields:
 | `toc_max_heading_level` | `number` | `3` | The max heading level shown in the table of contents. Must be between 2 and 6. |
 | `pagination_next` | <code>string \| null</code> | Next doc in the sidebar | The ID of the documentation you want the "Next" pagination to link to. Use `null` to disable showing "Next" for this page. |
 | `pagination_prev` | <code>string \| null</code> | Previous doc in the sidebar | The ID of the documentation you want the "Previous" pagination to link to. Use `null` to disable showing "Previous" for this page. |
-| `parse_number_prefixes` | `boolean` | `numberPrefixParser` plugin option | Whether number prefix parsing is disabled on this doc. See also [Using number prefixes](/docs/sidebar#using-number-prefixes). |
+| `parse_number_prefixes` | `boolean` | `numberPrefixParser` plugin option | Whether number prefix parsing is disabled on this doc. See also [Using number prefixes](/docs/sidebar/autogenerated#using-number-prefixes). |
 | `custom_edit_url` | <code>string \| null</code> | Computed using the `editUrl` plugin option | The URL for editing this document. Use `null` to disable showing "Edit this page" for this page. |
 | `keywords` | `string[]` | `undefined` | Keywords meta tag for the document page, for search engines. |
 | `description` | `string` | The first line of Markdown content | The description of your document, which will become the `<meta name="description" content="..."/>` and `<meta property="og:description" content="..."/>` in `<head>`, used by search engines. |