[18.1.1][BUG][`clang-tidy`][`bugprone-inc-dec-in-conditions`] `decltype` should not count as a variable "reference"

[Jacobfaib]

The new bugprone-inc-dec-in-conditions should not consider decltype() to be a reference of a variable when emitting this check.

int main()
{
    auto foo = 0;
    auto bar = 0;
    if (++foo < static_cast<decltype(foo)>(bar)) { }
    return 0;
}

[<source>:6:9: warning: incrementing and referencing a variable in a complex condition can cause unintended side-effects due to C++'s order of evaluation, consider moving the modification outside of the condition to avoid misunderstandings [bugprone-inc-dec-in-conditions]](javascript:;)
    6 |     if (++foo < static_cast<decltype(foo)>(bar)) { }
      |         ^
[<source>:6:38: note: variable is referenced here](javascript:;)
    6 |     if (++foo < static_cast<decltype(foo)>(bar)) { }
      |                                      ^
1 warning generated.

https://godbolt.org/z/6ahz8qea7

Expected Behavior

No diagnostics emitted for the above code, or, if this check intends to catch ++foo itself, have the diagnostic reference the increment itself.

[PiotrZSL]

Will be fixed in 19.0.