Show Subroutine Signatures

[bscan]

I would like to be able to view subroutine signatures as I type. This is how it looks in Python:

In Perl, we have the coderefs available for introspection. We should be able to deparse the coderef, inspect it, and return the signature. Make sure to remove $self if being called using -> notation. This task will likely be very tricky as it encompasses an end-to-end new feature.

https://stackoverflow.com/questions/63836449/how-do-i-get-the-signature-of-a-subroutine-in-runtime

https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_signatureHelp