[librsvg] (23 commits) ...Merge branch 'gi-docgen' into 'main'

[Marge Bot <marge-bot src gnome org>]

Summary of changes:

  eff053d... rsvg.h - first pass at conversion to Markdown
  13b9709... rsvg-features.h - first pass at conversion to Markdown
  3da89b7... rsvg-cairo.h: first pass at conversion to Markdown
  7f1b660... fix: rsvg.h
  a89fd3f... Remove comment block with duplicated section name
  50213bf... Add missing description for RsvgHandleFlags
  f1c0096... Add a few missing Returns:
  a4aa315... Fix docstrings for properties
  f7c6264... Missing docs for a no-op function.
  2f67661... Move all the introductory material to overview.xml
  94cbc24... Convert the individual chapters to Markdown
  a24f2c3... Initial TOML configuration for gi-docgen
  0e6ba74... Include "Title:" headings in the chapters so they get shown
  4fceed9... configure.ac: require gi-docgen
  cd3c411... doc/Makefile.am - Build the docs with gi-docgen; remove the
  cc11680... Remove gtk-doc detritus from configure.ac et al
  f62d3f2... Install gi-docgen during the CI
  05280db... Remove --enable-gtk-doc arguments from the CI scripts
  14c3699... RELEASING.md: Update to not mention --enable-gtk-doc
  a93ac54... tools/docker/*/Dockerfile - install gi-docgen
  2cb5a27... Install gi-docgen for the msys2 job
  c64613e... Update COMPILING.md for gi-docgen and docutils
  65b4f14... Merge branch 'gi-docgen' into 'main'