fa87f8feb7 doc: Clarify C++20 comments (MarcoFalke)
Pull request description:
Turns out "class template argument deduction for aggregates" is one of the few things implemented only in recent compilers, see https://en.cppreference.com/w/cpp/compiler_support/20
So clarify the comments.
ACKs for top commit:
hebasto:
ACK fa87f8feb7, I verified the code with clang-{16,17}.
Tree-SHA512: f6d20f946cb6f8e34db224e074ed8f9dfa598377c066d1b58a8feb9e64d007444f1e2c0399e91a3e282fd5d59f90e0d7df90aa3956824d96bc78070ee12f603c