Add incomplete tree-sitter-c-sharp package

[Benjamin-Davies]

Add bindings for tree-sitter-c-sharp.

Even though it is incomplete, partial support is better than none (IMHO). Also, it is my understanding that it is easy to update bindings if the base package changes, because of the way that this project is structured.

C# is a very popular language, and I would love to see it supported in the tools that depend on this library. I am particularly excited for semantic, (link to C# issue on that repo) as it is likely to become the base of GitHub's Code Navigation.

[robrix]

Good call 👍

[damieng]

C# support is now quite complete, putting a PR together now.

[patrickt]

@damieng Awesome! Next step (sorry for telling you these things piecemeal; we’re currently fixing the docs!) is to add a semantic-c-sharp package in https://github.com/github/semantic, implement the required ToTags instances, integrate C# support into the CLI, and write some tests. Then the way forward for C# will be cleared technologically: our schedules and behind-the-scenes operational concerns (database capacity, traffic analysis, and the like) will determine when support will land. Thank you so much for all your hard work!