Docs: Add a "seealso" section to the module docs (#45949)

* Docs: Add a separate  "seealso" section to the module docs
to list related modules and/or related references. This clears up the notes
section for things that are actual notes.

So you can add a section in your module documentation and four types of
references are possible.

    seealso:

    # Reference by module name
    - module: aci_tenant

    # Reference by module name, including description
    - module: aci_tenant
      description: ACI module to create tenants on a Cisco ACI fabric.

    # Reference by rST documentation anchor
    - ref: aci_guide
      description: Detailed information on how to manage your ACI infrastructure using Ansible.

    # Reference by Internet resource
    - name: APIC Management Information Model reference
      description: Complete reference of the APIC object model.
      link: https://developer.cisco.com/docs/apic-mim-ref/

This PR also includes:

- Implements ansible-doc support
- Implements schema support for the seealso options
- Updates to the development documentation
- Rename filter convert_symbols_to_format to rst_ify, cfr the existing html_ify and tty_ify filters
  - This makes the existing template a lot easier to read and fixes the confusion I had myself rereading the template (again).
- We fixed the possible suboption types (which was limited to 'bool' only)

* Use latest stable instead of devel docs

docs/bin/plugin_formatter.py

@@ -207,6 +207,7 @@ def get_plugin_info(module_dir, limit_to=None, verbose=False):
             :aliases: set of aliases to this module name
             :metadata: The modules metadata (as recorded in the module)
             :doc: The documentation structure for the module
+            :seealso: The list of dictionaries with references to related subjects
             :examples: The module's examples
             :returndocs: The module's returndocs
 
@@ -363,7 +364,7 @@ def jinja2_environment(template_dir, typ, plugin_type):
 
     templates = {}
     if typ == 'rst':
-        env.filters['convert_symbols_to_format'] = rst_ify
+        env.filters['rst_ify'] = rst_ify
         env.filters['html_ify'] = html_ify
         env.filters['fmt'] = rst_fmt
         env.filters['xline'] = rst_xline

docs/docsite/rst/dev_guide/developing_modules_documenting.rst

@@ -224,7 +224,34 @@ All fields in the ``DOCUMENTATION`` block are lower-case. All fields are require
 :notes:
 
   * Details of any important information that doesn't fit in one of the above sections.
-  * For example, whether ``check_mode`` is or is not supported, or links to external documentation.
+  * For example, whether ``check_mode`` is or is not supported.
+
+:seealso:
+
+  * A list of references to other modules, documentation or Internet resources
+  * A reference can be one of the following formats:
+
+
+    .. code-block:: yaml+jinja
+
+        seealso::
+
+        # Reference by module name
+        - module: aci_tenant
+
+        # Reference by module name, including description
+        - module: aci_tenant
+          description: ACI module to create tenants on a Cisco ACI fabric.
+
+        # Reference by rST documentation anchor
+        - ref: aci_guide
+          description: Detailed information on how to manage your ACI infrastructure using Ansible.
+
+        # Reference by Internet resource
+        - name: APIC Management Information Model reference
+          description: Complete reference of the APIC object model.
+          link: https://developer.cisco.com/docs/apic-mim-ref/
+
 
 Linking within module documentation
 -----------------------------------
@@ -239,7 +266,8 @@ You can link from your module documentation to other module docs, other resource
 
 .. note::
 
-  To refer a collection of modules, use ``C(..)``, e.g. ``Refer to the C(win_*) modules.``
+    - To refer a collection of modules, use ``C(..)``, e.g. ``Refer to the C(win_*) modules.``
+    - Because it stands out better, using ``seealso`` is preferred for general references over the use of notes or adding links to the description.
 
 Documentation fragments
 -----------------------
@@ -248,10 +276,13 @@ If you're writing multiple related modules, they may share common documentation,
 
 For example, all AWS modules should include::
 
+.. code-block:: yaml+jinja
+
     extends_documentation_fragment:
         - aws
         - ec2
 
+
 You can find more examples by searching for ``extends_documentation_fragment`` under the Ansible source tree.
 
 .. _examples_block:

docs/templates/plugin.rst.j2

@@ -11,7 +11,7 @@
 {% endfor %}
 
 {% if short_description %}
-{%   set title = module + ' - ' + short_description|convert_symbols_to_format %}
+{%   set title = module + ' - ' + short_description | rst_ify %}
 {% else %}
 {%   set title = module %}
 {% endif %}
@@ -39,9 +39,9 @@
 DEPRECATED
 ----------
 {# use unknown here? skip the fields? #}
-:Removed in Ansible: version: @{ deprecated['removed_in'] | default('') | string | convert_symbols_to_format }@
-:Why: @{ deprecated['why'] | default('') | convert_symbols_to_format }@
-:Alternative: @{ deprecated['alternative'] | default('')|  convert_symbols_to_format }@
+:Removed in Ansible: version: @{ deprecated['removed_in'] | default('') | string | rst_ify }@
+:Why: @{ deprecated['why'] | default('') | rst_ify }@
+:Alternative: @{ deprecated['alternative'] | default('') | rst_ify }@
 
 
 {% endif %}
@@ -51,10 +51,10 @@ Synopsis
 {% if description -%}
 
 {%   if description is string -%}
-- @{ description | convert_symbols_to_format }@
+- @{ description | rst_ify }@
 {%   else %}
 {%     for desc in description %}
-- @{ desc | convert_symbols_to_format }@
+- @{ desc | rst_ify }@
 {%     endfor %}
 {%   endif %}
 
@@ -75,7 +75,7 @@ The below requirements are needed on the local master node that executes this @{
 {%   endif %}
 
 {%   for req in requirements %}
-- @{ req | convert_symbols_to_format }@
+- @{ req | rst_ify }@
 {%   endfor %}
 
 {% endif %}
@@ -206,17 +206,40 @@ Parameters
 {% endif %}
 
 {% if notes -%}
-
 Notes
 -----
 
 .. note::
 {%   for note in notes %}
-    - @{ note | convert_symbols_to_format }@
+   - @{ note | rst_ify }@
 {%   endfor %}
 
 {% endif %}
 
+{% if seealso -%}
+See Also
+--------
+
+.. seealso::
+
+{% for item in seealso %}
+{%   if item.module is defined and item.description is defined %}
+   :ref:`Module @{ item.module }@ <@{ item.module }@_module>`
+       @{ item.description | rst_ify }@
+{%   elif item.module is defined %}
+   :ref:`@{ item.module }@_module`
+      The official documentation on the **@{ item.module }@** module.
+{%   elif item.name is defined and item.link is defined and item.description is defined %}
+   `@{ item.name }@ <@{ item.link }@>`_
+       @{ item.description | rst_ify }@
+{%   elif item.ref is defined and item.description is defined %}
+   :ref:`@{ item.ref }@`
+       @{ item.description | rst_ify }@
+{%   endif %}
+{% endfor %}
+
+{% endif %}
+
 {% if examples or plainexamples -%}
 
 Examples
@@ -421,7 +444,7 @@ please refer to this `Knowledge Base article <https://access.redhat.com/articles
 
 {% else %}
 
-This @{ plugin_type }@ is flagged as **deprecated** and will be removed in version @{ deprecated['removed_in'] | default('') | string | convert_symbols_to_format }@. For more information see `DEPRECATED`_.
+This @{ plugin_type }@ is flagged as **deprecated** and will be removed in version @{ deprecated['removed_in'] | default('') | string | rst_ify }@. For more information see `DEPRECATED`_.
 
 {% endif %}