[clang-tools-extra] [clang-tidy] Enable `modernize-return-braced-init-list`'s tests in C++11 (PR #158196)

[Carlos Galvez via cfe-commits]

carlosgalvezp wrote:

Nah I don't think we should make it mandatory. There are checks that don't require any specific standard, there it would make sense to keep whatever the default is. 

I would say it makes sense to specify it in the test when the check also specifies it as requirement.

https://github.com/llvm/llvm-project/pull/158196