[clang-tidy] `ClangTidyOptions` should not contain `optional` values

[carlosgalvezp]

This leads to each and every client of the options having to check if that optional contains a value, and make a decision about a default value, to be able to use the options. Or else assume there's a value and just get the value directly, risking UB if there was no value to begin with.

For example, here:

std::optional<bool> SystemHeaders;

The value for this option must either true or false, there's no such thing as an "unknown" value. The same probably applies to all other options, but I haven't checked carefully.

[llvmbot]

@llvm/issue-subscribers-clang-tidy

Author: Carlos Galvez (carlosgalvezp)

This leads to each and every client of the options having to check if that optional contains a value, and make a decision about a default value, to be able to use the options. Or else assume there's a value and just get the value directly, risking UB if there was no value to begin with.

For example, here:

std::optional<bool> SystemHeaders;

The value for this option must either true or false, there's no such thing as an "unknown" value. The same probably applies to all other options, but I haven't checked carefully.