A great idea I'm sure many will get use out of! One thing I can mention is that it's actually perfectly fine to do

style say_dialogue:
    hyperlink_functions (inline_tooltip_styler, inline_tooltip_clicked, inline_tooltip_hovered)

in the inline_tooltip.rpy file - Ren'Py just collects all the style declarations with the same name into one style at the end. It can be a little confusing but it works out well here so there's one less step for users!

I did also want to warn that you may want to be careful with your find-and-replace code - since it doesn't account for punctuation/spacing or sort by word length, something like `Elves` will always match before `The Elves`, for example, and you might also run into situations where you include `_("elves")` as a key but it highlights "elves" inside "themselves".

Thank you for making this!