improve inv plugin selectino for snippets (#74933)

* improve inv plugin selectino for snippets
* add warning on no snippet for inventory

changelogs/fragments/snippets_inv_select.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - ansible-doc, make inventory plugin selection for snippets generic and not a hardcoded list

lib/ansible/cli/doc.py

@@ -842,8 +842,9 @@ class DocCLI(CLI, RoleMixin):
         if context.CLIARGS['show_snippet']:
             if plugin_type not in SNIPPETS:
                 raise AnsibleError("Snippets are only available for the following plugin types: %s" % ', '.join(SNIPPETS))
-            if plugin_type == 'inventory' and plugin in ('yaml', 'toml'):
-                # not usable as other inventory plugins
+            if plugin_type == 'inventory' and doc.get('options') and not doc['options'].get('plugin'):
+                # these are 'configurable' but not intended for yaml type inventory sources, like ini or script
+                # so we cannot use as source for snippets
                 del doc['options']
             text = DocCLI.get_snippet_text(doc, plugin_type)
         else:
@@ -971,6 +972,8 @@ class DocCLI(CLI, RoleMixin):
             _do_lookup_snippet(text, doc)
         elif 'options' in doc:
             _do_yaml_snippet(text, doc)
+        elif ptype == 'inventory':
+            display.warning('Snippets are only available to inventory plugins with YAML type sources that can be used with the "auto" plugin.')
 
         text.append('')
         return "\n".join(text)