[clang-tidy] Improve documentation of bugprone-return-const-ref-from-parameter

[chrchr-github]

const std::vector<int>& f(std::vector<int>&&) = delete; // bugprone-return-const-ref-from-parameter without this
const std::vector<int>& f(const std::vector<int>& v) { return v; }

The presence of a deleted overload prevents the warning, so maybe that should be mentioned in the documentation? Currently, there is no indication given to the user on how to address this warning.
https://clang.llvm.org/extra/clang-tidy/checks/bugprone/return-const-ref-from-parameter.html