feature: lsp_incoming_calls and lsp_outgoing_calls support for Snacks.picker

[DanWlker]

Did you check the docs?

• [X] I have read all the snacks.nvim docs

Is your feature request related to a problem? Please describe.

fzf-lua and telescope both have lsp_incoming_calls and lsp_outgoing_calls, would be great if Snacks.picker supports it as well

Describe the solution you'd like

Support lsp_incoming_calls and lsp_outgoing_calls

Describe alternatives you've considered

Just using lsp_references

Additional context

No response