[Feature Request] Allow passing filters to `--doc`

[Stanzilla]

It would be very nice if we were able to pass filters to the --doc command to only document specific namespaces.

Example:

lua-language-server --doc="../../.." --doc-filter="MyNameSpace" --doc_out_path="."

Would only output documentation for MyNameSpace and every member like MyNameSpace.Private etc.

For the json output formal I can do this easily via something like

jq '[.[] | select(.name | index("MyNameSpace") != -1)]' doc.json > output.json but for the markdown output, it would be fairly difficult.