Add FAQ entry "Which programming language is fastest?"

[tetrapod00]

Compares the performance of C#, GDScript, and C++.

Extracts the programming language comparison from #7538 and moves it to a dedicated FAQ entry. Now feel free to argue about the characterization of your favorite language 😄 .

CC @Calinou, this is largely based on your revised description from that PR.

(At some point I might like to add a dedicated "Which language should I use?" entry to the FAQ, but it's not clean to add right now because the current FAQ is designed to sell you on GDScript. The current "Which programming languages are supported in Godot?" and "What is GDScript and why should I use it?" combined cover this topic already.)

[mhilbrunner]

As noted in #10286, I'm in favor of this PR and removing that whole comparison from the C# docs.

[dsnopek]

Is it worth noting that C++ in modules can be faster than C++ in GDExtension (also because of marshalling, like pointed out for C#)? Or is that too much information?

[tetrapod00]

Is it worth noting that C++ in modules can be faster than C++ in GDExtension (also because of marshalling, like pointed out for C#)? Or is that too much information?

I think this question and answer could be up to 50-100% longer than it curently is if all the information added is concise and relevant. The FAQ has some long answers already. The nuances of C++ modules and C++ with GDExtension were outside my personal expertise so I didn't say much about it.

[skyace65]

Looks good to me, it just needs to be rebased since #10286 was merged.

[tetrapod00]

Before merging, I wanted to give Calinou (and maintainers for GDExtension and C#) a bit more of a chance to look over if they find time, since it's based on their previous work. If that doesn't happen, we can always make improvements later

[skyace65]

Thanks!

[mhilbrunner]

Cherrypicked to 4.3 in #10347.