Fix misrendered sections in manpage generation

This change fixes bugs in the manpage generator that existed since it
was first added.

It exposes CLI `ARGUMENTS` value to manpage templates.

Before this change, the code contained a typo, causing the `for`-loop
iterate over individual characters of the `'ARGUMENTS'` string rather
than iterating over a tuple. A missing comma was at fault.

The updated code gets rid of the `for`-loop and conditionals since it
seems to have been a premature complexity increase and no other things
than `'ARGUMENTS'` were ever added into the broken iterable.

The functional change is that `arguments` is now always present in the
Jinja2 context, unlike being missing sometimes because of the previous
design (not that it was ever present, because of the bug! sigh...)

The Jinja2 templates perform an `{% if arguments %}` check, letting
the template engine silently ignore the missing variable. The clause
was always falsy, meaning that the arguments section was not included
in the manpages for at least the last 6 years. With this fix, it will
be.

This patch also deduplicates calling `opt_doc_list` @ generate_man.

It was called late in the execution, more times than necessary. This
patch makes sure it happens once by putting it at the top of the scope.

It fixes rendering library and inventory in manpages.

The corresponding Jinja2 templates have blocks wrapped with
conditionals like `{% if inventory %}` and `{% if library %}` but said
variables were never injected into the context, nor were they even
deduced on the Python side of the generator. This means that the
conditional clauses were always falsy, never showing the portions of
the manpages.

The Python script has hints for how the `inventory` variable was to be
calculated, which is confirmed through the Git paleontology efforts.

The block of code that references to the `inventory` bit was
incorrectly checking a variable with a list of nested objects for the
presence of a string which was never going to work.

This patch fixes this check by verifying the CLI flag against the
correct variable containing a list of options and exposes it to the
Jinja2 templates.
It also exposes the `library` variable in a similar way.

The block displaying other binaries in Sphinx CLI docs has been
synchronized with the manpage template.
Previously, the current binary was displayed also. This patch gets rid
of the unwanted trailing comma there too.

Finally, the CLI executables list in the manpage template now reuses
the same variable as the RST template that doesn't need any
post-processing in Jinja2.
Before, it was already used in the RST template so this patch aligns
both templates to use the same logic as they got out-of-sync over time.

PR #80450.

docs/templates/cli_rst.j2

@@ -158,4 +158,4 @@ Ansible is released under the terms of the GPLv3+ License.
 See also
 ========
 
-{% for other in cli_bin_name_list|sort %}:manpage:`{{other}}(1)`,  {% endfor %}
+{% for other in cli_bin_name_list|sort %}{% if other != cli_name %}:manpage:`{{other}}(1)`{% if not loop.last %}, {% endif %}{% endif %}{% endfor %}

docs/templates/man.j2

@@ -1,6 +1,5 @@
-{% set name = ('ansible' if cli == 'adhoc' else 'ansible-%s' % cli) -%}
+{{ cli_name }}
-{{name}}
+{{ '=' * ( cli_name|length|int ) }}
-{{ '=' * ( name|length|int ) }}
 
 {{ '-' * ( short_desc|default('')|string|length|int ) }}
 {{short_desc|default('')}}
@@ -14,7 +13,7 @@
 
 SYNOPSIS
 --------
-{{ usage|replace('%prog', name) }}
+{{ usage|replace('%prog', cli_name) }}
 
 
 DESCRIPTION
@@ -120,7 +119,7 @@ Ansible is released under the terms of the GPLv3 license.
 SEE ALSO
 --------
 
-{% for other in cli_list|sort %}{% if other != cli %}**ansible{% if other != 'adhoc' %}-{{other}}{% endif %}** (1){% if not loop.last %}, {% endif %}{% endif %}{% endfor %}
+{% for other in cli_bin_name_list|sort %}{% if other != cli_name %}**{{ other }}** (1){% if not loop.last %}, {% endif %}{% endif %}{% endfor %}
 
 Extensive documentation is available in the documentation site:
 <https://docs.ansible.com>.

hacking/build_library/build_ansible/command_plugins/generate_man.py

@@ -127,6 +127,7 @@ def opts_docs(cli_class_name, cli_module_name):
         pass
 
     # base/common cli info
+    cli_options = opt_doc_list(cli.parser)
     docs = {
         'cli': cli_module_name,
         'cli_name': cli_name,
@@ -135,22 +136,18 @@ def opts_docs(cli_class_name, cli_module_name):
         'long_desc': trim_docstring(cli.__doc__),
         'actions': {},
         'content_depth': 2,
+        'options': cli_options,
+        'arguments': getattr(cli, 'ARGUMENTS', None),
     }
     option_info = {'option_names': [],
-                   'options': [],
+                   'options': cli_options,
                    'groups': []}
 
-    for extras in ('ARGUMENTS'):
-        if hasattr(cli, extras):
-            docs[extras.lower()] = getattr(cli, extras)
-
-    common_opts = opt_doc_list(cli.parser)
     groups_info = get_option_groups(cli.parser)
     shared_opt_names = []
-    for opt in common_opts:
+    for opt in cli_options:
         shared_opt_names.extend(opt.get('options', []))
 
-    option_info['options'] = common_opts
     option_info['option_names'] = shared_opt_names
 
     option_info['groups'].extend(groups_info)
@@ -211,7 +208,6 @@ def opts_docs(cli_class_name, cli_module_name):
     action_depth = get_actions(cli.parser, docs)
     docs['content_depth'] = action_depth + 1
 
-    docs['options'] = opt_doc_list(cli.parser)
     return docs
 
 
@@ -292,11 +288,14 @@ class GenerateMan(Command):
 
             # add rest to vars
             tvars = allvars[cli_name]
-            tvars['cli_list'] = cli_list
             tvars['cli_bin_name_list'] = cli_bin_name_list
             tvars['cli'] = cli_name
-            if '-i' in tvars['options']:
+            if '-i' in tvars['option_names']:
+                tvars['inventory'] = True
                 print('uses inventory')
+            if '-M' in tvars['option_names']:
+                tvars['library'] = True
+                print('uses library')
 
             manpage = template.render(tvars)
             filename = os.path.join(output_dir, doc_name_formats[output_format] % tvars['cli_name'])