Show individual function parameter documentation when hovering over said parameter or its inlay hint.

[jansol]

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• [X] Completed

Describe the feature

When hovering over a function I get its signature and docstring displayed, nice. In the screenshot you can also see the inlay hints for the function parameters. It would be nice if hovering over one of those would show the type and docstring (if available) of that particular parameter for quick referencing.

When hovering over the actual argument passed in (e.g. &pfd here), the hover tooltip shows the description of pfd. It would be neat to also show the function parameter type & docstring there in addition. So you could see both the expected and actual parameter info at a glance. In fact, for literal values such as the 1 here this appears to already happen:

Tangentially related to #4879 and #5155