Display doc comments on hover

[Caleb-o]

Is your feature request related to a problem? Please describe.
If some functions, types etc have doc comments, a hover on that item should show it. This helps to provide necessary information, without having to track down the code and read it in the place it was written.

Describe the solution you'd like
Show doc comments under the signature on hover

Describe alternatives you've considered
N/A

Additional context
What this could look like, using Rust as an example:

Doc comments: