[clang-tools-extra] [clang-tidy] support query based custom check (PR #131804)

[Piotr Zegar via cfe-commits]

PiotrZSL wrote:

> I think flattening the configuration items will only reduce readability, because we cannot define a YAML schema for it.
If we put that entire YAML under "custom-call-main-function.Config", that would also be fine. Thing is that with this there could be a way to make all chances in "custom" module without modify tool core. In such case we could have;
custom-call-main-function.Config and custom-call-main-function.Engine, and in such case entire config parsing would be actually inside a check code, and creating different base checks could also be possible.


https://github.com/llvm/llvm-project/pull/131804