docs(v2): Reorganize/split the guides doc sections (#3975)

* docs reorg

* refactor docs/markdown features section

* fix broken links after docs refactor

website/docs/guides/markdown-features/markdown-features-inline-toc.mdx

@@ -0,0 +1,117 @@
+---
+id: inline-toc
+title: Inline TOC
+description: Using inline table-of-contents inside Docusaurus Markdown
+slug: /markdown-features/inline-toc
+---
+
+import BrowserWindow from '@site/src/components/BrowserWindow';
+
+Each markdown document displays a tab of content on the top-right corner.
+
+But it is also possible to display an inline table of contents directly inside a markdown document, thanks to MDX.
+
+## Full table of contents
+
+The `toc` variable is available in any MDX document, and contain all the top level headings of a MDX document.
+
+```jsx
+import TOCInline from '@theme/TOCInline';
+
+<TOCInline toc={toc} />;
+```
+
+import TOCInline from '@theme/TOCInline';
+
+<BrowserWindow>
+
+<TOCInline toc={toc} />
+
+</BrowserWindow>
+
+## Custom table of contents
+
+The `toc` props is just a list of table of contents items:
+
+```ts
+type TOCItem = {
+  value: string;
+  id: string;
+  children: TOCItem[];
+};
+```
+
+You can create this TOC tree manually, or derive a new TOC tree from the `toc` variable:
+
+```jsx
+import TOCInline from '@theme/TOCInline';
+
+<TOCInline
+  toc={
+    // Only show 3th and 5th top-level heading
+    [toc[2], toc[4]]
+  }
+/>;
+```
+
+<BrowserWindow>
+
+<TOCInline toc={[toc[2], toc[4]]} />
+
+</BrowserWindow>
+
+---
+
+:::caution
+
+The underlying content is just an example to have more table-of-contents items available in current page.
+
+:::
+
+## Example Section 1
+
+Lorem ipsum
+
+### Example Subsection 1 a
+
+Lorem ipsum
+
+### Example Subsection 1 b
+
+Lorem ipsum
+
+### Example Subsection 1 c
+
+Lorem ipsum
+
+## Example Section 2
+
+Lorem ipsum
+
+### Example Subsection 2 a
+
+Lorem ipsum
+
+### Example Subsection 2 b
+
+Lorem ipsum
+
+### Example Subsection 2 c
+
+Lorem ipsum
+
+## Example Section 3
+
+Lorem ipsum
+
+### Example Subsection 3 a
+
+Lorem ipsum
+
+### Example Subsection 3 b
+
+Lorem ipsum
+
+### Example Subsection 3 c
+
+Lorem ipsum