doc: Update manuals bespoke syntax

doc: add figure definition to bespoke syntax reference

doc: add example definition to bespoke syntax reference

doc: add footnote definition to beskpoke syntax reference

The usage of footnotes in the manuals is not the one documented
in markdown-it-py: https://python-markdown.github.io/extensions/footnotes/

doc: add inline comment definition to beskpoke syntax reference

doc: add typographic replacements to beskpoke syntax reference

doc: Fix rendering of bespoke syntax reference

doc: remove references to DocBook in the NixOS manual

doc: add entry on lack of HTML support

doc: Minor improvement

doc: update typographic replacements entry in beskpoke syntax reference

doc: add link reference definitions to beskpoke syntax reference

doc: fix footnote definition in beskpoke syntax reference

doc: Minor improvements from code review

Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>

doc/README.md

@@ -71,6 +71,11 @@ If you **omit a link text** for a link pointing to a section, the text will be s
 
 This syntax is taken from [MyST](https://myst-parser.readthedocs.io/en/latest/using/syntax.html#targets-and-cross-referencing).
 
+
+#### HTML
+
+Inlining HTML is not allowed. Parts of the documentation gets rendered to various non-HTML formats, such as man pages in the case of NixOS manual.
+
 #### Roles
 
 If you want to link to a man page, you can use `` {manpage}`nix.conf(5)` ``. The references will turn into links when a mapping exists in [`doc/manpage-urls.json`](./manpage-urls.json).
@@ -265,6 +270,79 @@ You, as the writer of documentation, are still in charge of its content.
     _Default:_ the output path's hash.
   ```
 
+#### Examples
+
+To define a referenceable figure use the following fencing:
+
+```markdown
+:::{.example #an-attribute-set-example}
+# An attribute set example
+
+You can add text before
+
+    ```nix
+    { a = 1; b = 2;}
+    ```
+
+and after code fencing
+:::
+```
+
+Defining examples through the `example` fencing class adds them to a "List of Examples" section after the Table of Contents.
+Though this is not shown in the rendered documentation on nixos.org.
+
+#### Figures
+
+To define a referencable figure use the following fencing:
+
+```markdown
+::: {.figure #nixos-logo}
+# NixOS Logo
+![NixOS logo](./nixos_logo.png)
+:::
+```
+
+Defining figures through the `figure` fencing class adds them to a `List  of Figures` after the `Table of Contents`.
+Though this is not shown in the rendered documentation on nixos.org.
+
+#### Footnotes
+
+To add a foonote explanation, use the following syntax:
+
+```markdown
+Sometimes it's better to add context [^context] in a footnote.
+
+[^context]: This explanation will be rendered at the end of the chapter.
+```
+
+#### Inline comments
+
+Inline comments are supported with following syntax:
+
+```markdown
+<!-- This is an inline comment -->
+```
+
+The comments will not be rendered in the rendered HTML.
+
+#### Link reference definitions
+
+Links can reference a label, for example, to make the link target reusable:
+
+```markdown
+::: {.note}
+Reference links can also be used to [shorten URLs][url-id] and keep the markdown readable.
+:::
+
+[url-id]: https://github.com/NixOS/nixpkgs/blob/19d4f7dc485f74109bd66ef74231285ff797a823/doc/README.md
+```
+
+This syntax is taken from [CommonMark](https://spec.commonmark.org/0.30/#link-reference-definitions).
+
+#### Typographic replacements
+
+Typographic replacements are enabled. Check the [list of possible replacement patterns check](https://github.com/executablebooks/markdown-it-py/blob/3613e8016ecafe21709471ee0032a90a4157c2d1/markdown_it/rules_core/replacements.py#L1-L15).
+
 ## Getting help
 
 If you need documentation-specific help or reviews, ping [@NixOS/documentation-reviewers](https://github.com/orgs/nixos/teams/documentation-reviewers) on your pull request.

nixos/doc/manual/contributing-to-this-manual.chapter.md

@@ -1,6 +1,6 @@
 # Contributing to this manual {#chap-contributing}
 
-The [DocBook] and CommonMark sources of the NixOS manual are in the [nixos/doc/manual](https://github.com/NixOS/nixpkgs/tree/master/nixos/doc/manual) subdirectory of the [Nixpkgs](https://github.com/NixOS/nixpkgs) repository.
+The sources of the NixOS manual are in the [nixos/doc/manual](https://github.com/NixOS/nixpkgs/tree/master/nixos/doc/manual) subdirectory of the [Nixpkgs](https://github.com/NixOS/nixpkgs) repository.
 This manual uses the [Nixpkgs manual syntax](https://nixos.org/manual/nixpkgs/unstable/#sec-contributing-markup).
 
 You can quickly check your edits with the following:

nixos/doc/manual/development/writing-documentation.chapter.md

@@ -7,7 +7,7 @@ worthy contribution to the project.
 
 ## Building the Manual {#sec-writing-docs-building-the-manual}
 
-The DocBook sources of the [](#book-nixos-manual) are in the
+The sources of the [](#book-nixos-manual) are in the
 [`nixos/doc/manual`](https://github.com/NixOS/nixpkgs/tree/master/nixos/doc/manual)
 subdirectory of the Nixpkgs repository.
 
@@ -29,65 +29,3 @@ nix-build nixos/release.nix -A manual.x86_64-linux
 When this command successfully finishes, it will tell you where the
 manual got generated. The HTML will be accessible through the `result`
 symlink at `./result/share/doc/nixos/index.html`.
-
-## Editing DocBook XML {#sec-writing-docs-editing-docbook-xml}
-
-For general information on how to write in DocBook, see [DocBook 5: The
-Definitive Guide](https://tdg.docbook.org/tdg/5.1/).
-
-Emacs nXML Mode is very helpful for editing DocBook XML because it
-validates the document as you write, and precisely locates errors. To
-use it, see [](#sec-emacs-docbook-xml).
-
-[Pandoc](https://pandoc.org/) can generate DocBook XML from a multitude of
-formats, which makes a good starting point. Here is an example of Pandoc
-invocation to convert GitHub-Flavoured MarkDown to DocBook 5 XML:
-
-```ShellSession
-pandoc -f markdown_github -t docbook5 docs.md -o my-section.md
-```
-
-Pandoc can also quickly convert a single `section.xml` to HTML, which is
-helpful when drafting.
-
-Sometimes writing valid DocBook is too difficult. In this case,
-submit your documentation updates in a [GitHub
-Issue](https://github.com/NixOS/nixpkgs/issues/new) and someone will
-handle the conversion to XML for you.
-
-## Creating a Topic {#sec-writing-docs-creating-a-topic}
-
-You can use an existing topic as a basis for the new topic or create a
-topic from scratch.
-
-Keep the following guidelines in mind when you create and add a topic:
-
--   The NixOS [`book`](https://tdg.docbook.org/tdg/5.0/book.html)
-    element is in `nixos/doc/manual/manual.xml`. It includes several
-    [`parts`](https://tdg.docbook.org/tdg/5.0/book.html) which are in
-    subdirectories.
-
--   Store the topic file in the same directory as the `part` to which it
-    belongs. If your topic is about configuring a NixOS module, then the
-    XML file can be stored alongside the module definition `nix` file.
-
--   If you include multiple words in the file name, separate the words
-    with a dash. For example: `ipv6-config.xml`.
-
--   Make sure that the `xml:id` value is unique. You can use abbreviations
-    if the ID is too long. For example: `nixos-config`.
-
--   Determine whether your topic is a chapter or a section. If you are
-    unsure, open an existing topic file and check whether the main
-    element is chapter or section.
-
-## Adding a Topic to the Book {#sec-writing-docs-adding-a-topic}
-
-Open the parent CommonMark file and add a line to the list of
-chapters with the file name of the topic that you created. If you
-created a `section`, you add the file to the `chapter` file. If you created
-a `chapter`, you add the file to the `part` file.
-
-If the topic is about configuring a NixOS module, it can be
-automatically included in the manual by using the `meta.doc` attribute.
-See [](#sec-meta-attributes) for an explanation.