docs: Add missing type and parameter in custom-rules.rst (#1764)

* docs: Add missing type and parameter in custom-rules.rst

* docs: Add type for file parameter

Co-authored-by: Simon - SIPR <[email protected]>
Co-authored-by: Sorin Sbarnea <[email protected]>

docs/custom-rules.rst

@@ -46,18 +46,23 @@ An example rule using ``matchtask`` is:
 
 .. code-block:: python
 
-    from typing import Any, Dict
+    from typing import TYPE_CHECKING, Any, Dict, Union
 
     import ansiblelint.utils
     from ansiblelint.rules import AnsibleLintRule
 
+    if TYPE_CHECKING:
+        from typing import Optional
+
+        from ansiblelint.file_utils import Lintable
+
     class TaskHasTag(AnsibleLintRule):
         id = 'EXAMPLE001'
         shortdesc = 'Tasks must have tag'
         description = 'Tasks must have tag'
         tags = ['productivity']
 
-        def matchtask(self, task: Dict[str, Any]) -> Union[bool,str]:
+        def matchtask(self, task: Dict[str, Any], file: 'Optional[Lintable]' = None) -> Union[bool,str]:
             # If the task include another task or make the playbook fail
             # Don't force to have a tag
             if not set(task.keys()).isdisjoint(['include','fail']):