[gi-docgen] (4 commits) ...Merge branch 'callback-ctype' into 'main'

[Emmanuele Bassi <ebassi src gnome org>]

Summary of changes:

  bff6c34... generate: Use the C type name for callback types (*)
  cd16ed7... indices: Include the callback ctype (*)
  ccc3af8... template: Handle callback types like all other types (*)
  e7fcc36... Merge branch 'callback-ctype' into 'main'

(*) This commit already existed in another branch; no separate mail sent