PYTHON-4940 - Add index hint as an explicit parameter for distinct command.

[NoahStapp]

We already supported hint for distinct() through kwargs, but we didn't mention it. Now we explicitly support it similarly to the other Collection methods.

[blink1073]

LGTM!

[blink1073]

Ah, except typing:

pymongo/synchronous/collection.py:3165: error: Incompatible types in assignment
(expression has type "Union[str, dict[str, Any]]", target has type "str") 
[assignment]
                cmd["hint"] = hint
                              ^~~~
pymongo/asynchronous/collection.py:3172: error: Incompatible types in
assignment (expression has type "Union[str, dict[str, Any]]", target has type
"str")  [assignment]
                cmd["hint"] = hint

[NoahStapp]

Ah, except typing:

pymongo/synchronous/collection.py:3165: error: Incompatible types in assignment
(expression has type "Union[str, dict[str, Any]]", target has type "str") 
[assignment]
                cmd["hint"] = hint
                              ^~~~
pymongo/asynchronous/collection.py:3172: error: Incompatible types in
assignment (expression has type "Union[str, dict[str, Any]]", target has type
"str")  [assignment]
                cmd["hint"] = hint

Fixed!

[ShaneHarvey]

We still need to add tests for this like we do for other helpers that accept hint.

[NoahStapp]

Tests besides the spec tests? The spec tests that verify this change were already present in our repo.

[ShaneHarvey]

Yes because we have python specific behavior, like accepting hint="str" and hint=[pairs].