Add another git submodule for C# called c-sharp-pro

[mjambon]

This uses tree_sitter_c_sharp_pro_ prefix in the C functions to avoid conflicts with the other C# parser so they can be linked into the same executable.

Checklist

• Any new parsing code was already published, integrated, and merged into Semgrep. DO NOT MERGE THIS PR BEFORE THE SEMGREP INTEGRATION WORK WAS COMPLETED.
• Change has no security implications (otherwise, ping the security team)

[aryx]

I thought it would have been simpler to use just one tree-sitter-chsarp, and update it here to the latest but update to a more
recent semgrep-c-sharp in pro, but maybe you're right it's simpler to separate them also here.

[aryx]

especially if you managed to avoid naming conflicts in C.

[aryx]

cc @yosefAlsuhaibani who might have to do something similar for another language (I don't remember which one).