[gi-docgen/wip/carlosg/multi-content-dir: 5/5] docs: Document --content-dir as a multi argument

[Carlos Garnacho <carlosg src gnome org>]

commit 9680876c405e632387dcaabf1358bf9cd18c802b
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sun Jun 6 00:29:03 2021 +0200

    docs: Document --content-dir as a multi argument
    
    This CLI argument can now be called several times to specify
    multiple sources of extra content. Document this use.

 docs/project-configuration.rst | 8 ++++----
 docs/tools/gen-index.rst       | 7 +++++--
 docs/tools/generate.rst        | 7 +++++--
 3 files changed, 14 insertions(+), 8 deletions(-)
---
diff --git a/docs/project-configuration.rst b/docs/project-configuration.rst
index 979ac05..6e95752 100644
--- a/docs/project-configuration.rst
+++ b/docs/project-configuration.rst
@@ -122,8 +122,8 @@ The following keys are used, if found:
 
 ``content_files`` = ``list(s)``
   A list of tuples. The first element of the tuple is a Markdown
-  file name, relative to the directory specified by the ``--content-dir``
-  command line argument; the second element of the tuple is the
+  file name, relative to the directories specified by the ``--content-dir``
+  command line arguments; the second element of the tuple is the
   title used for the link to the content file. When generating the
   API reference, gi-docgen will transform the Markdown file into
   an HTML one, using the same pre-processing filters applied to the
@@ -132,8 +132,8 @@ The following keys are used, if found:
   the namespace.
 
 ``content_images`` = ``list(s)``
-  A list of files, relative to the directory specified by the
-  ``--content-dir`` command line argument. The files will be copied
+  A list of files, relative to the directories specified by the
+  ``--content-dir`` command line arguments. The files will be copied
   in the root directory of the namespace.
 
 ``urlmap_file`` = ``s``
diff --git a/docs/tools/gen-index.rst b/docs/tools/gen-index.rst
index 5525221..5882ac0 100644
--- a/docs/tools/gen-index.rst
+++ b/docs/tools/gen-index.rst
@@ -40,8 +40,11 @@ OPTIONS
   Only load the introspection data, without generating the index.
 
 ``--content-dir DIR``
-  The directory for extra content, like additional files and images
-  specified in the project configuration file.
+  The directories for extra content, like additional files and images
+  specified in the project configuration file. This argument may be
+  called multiple times to specify several lookup directories, the
+  content files will be looked these directories in the same order
+  they are added.
 
 ``--output-dir DIR``
   Generates the index file under ``DIR``.
diff --git a/docs/tools/generate.rst b/docs/tools/generate.rst
index b36f22b..146d3e3 100644
--- a/docs/tools/generate.rst
+++ b/docs/tools/generate.rst
@@ -43,8 +43,11 @@ OPTIONS
   templates directory is inside the ``gi-docgen`` installation.
 
 ``--content-dir DIR``
-  The directory for extra content, like additional files and images
-  specified in the project configuration file.
+  The directories for extra content, like additional files and images
+  specified in the project configuration file. This argument may be
+  called multiple times to specify several lookup directories, content
+  files will be looked up in the content directories in the
+  same order they are added.
 
 ``--theme-name NAME``
   The name of the template to use. Overrides the name specified by