Suggestion: Make `@param;@return` available as code action

[chrisgrieser]

One really nice feature of the lua-lsp is that by typing --- above a function, we get the @param;@return suggestions which auto-inserts function annotation.

Would it be possible to make this feature available via code action as well? Right now, it takes a bit of repetitive work to get the annotations inserted. When at the function head: up, -. -, -, enter. By using a code action, this could be reduced to one hotkey (and depending on your editor, maybe one extra enter).

Another benefit would be that making this available as code action would increase the discoverability of this feature. For a while, I didn't know that this very useful feature even existed. By being a code action, it would be far easier to discover for new users.