Add fuzzy search to documentation search

[Kartopod]

#98278 implemented Fuzzy string matching to the Quick Open Scene window (and other related windows).

Extending the same behaviour to the documentation 'Search help' window would be a great QOL improvement.

[Calinou]

I'm not sure if the fuzzy search algorithm will be able to cope with the entire class reference's size in terms of performance.

That said, it should be straightforward to make the help search style-insensitive by stripping underscores from the text that the search string will search for. This way, searching for moveandslide will make move_and_slide appear.

[Kartopod]

Makes sense, and even that would be a great improvement!