Adding note about implicit groups (#82580)

clarifying usage in conjunction with use_group_vars

changelogs/fragments/82580_constructed.yml

@@ -0,0 +1,2 @@
+minor_changes:
+  - "constructed inventory plugin - Adding a note that only group_vars of explicit groups are loaded (https://github.com/ansible/ansible/pull/82580)."

lib/ansible/plugins/inventory/constructed.py

@@ -25,6 +25,8 @@ DOCUMENTATION = '''
                 - The host_group_vars (enabled by default) 'vars plugin' is the one responsible for reading host_vars/ and group_vars/ directories.
                 - This will execute all vars plugins, even those that are not supposed to execute at the 'inventory' stage.
                   See vars plugins docs for details on 'stage'.
+                - Implicit groups, such as 'all' or 'ungrouped', need to be explicitly defined in any previous inventory to apply the
+                  corresponding group_vars
             required: false
             default: false
             type: boolean