[LS] No function signature on hover

[jribbink]

Issue to be solved

It's unclear what the function signature of a member function is using the LS. E.g. in the example below, I have an unused result, but not actionable solution as I cannot hover to see how to handle the return type

Suggested Solution

Fix (or implement?) the hover to make it clear to users what the inputs/output are.

[bluesign]

Unrelated but: Doesnt this give an error? Can you share the snippet

[turbolent]

#636 should improve go-to-definition and hover for types and members, even across files