[llvm] [docs][CMake] Add CMakePreset, improve VS documentation (PR #84760)

[Tobias Hieta via llvm-commits]

tru wrote:

> I personally don't get on with the built-in CMake support within Visual Studio. I've got no issue with documenting how to use it or adding "sensible" defaults (I have a suspicion that there is no specific "sensible" default for any given user), but I would prefer us avoiding stating that one way is preferred above another way, especially without an RFC discussion to formalise this stance: let each user decide for themselves which method they'd prefer to use.

That's fine, I can change the documentation to make it clear it's a choice and without us pushing people either way.

> Another thought: since presumably no build bot will be configured to use the files you're adding, what's stopping them rotting?

Good point, but I don't think this will be a huge issue since I tried to use very common options. But if this is a problem I can probably do a github workflow for it down the line.

https://github.com/llvm/llvm-project/pull/84760