Use C++ features now available

[ProgramMax]

The deprecation schedule has us supporting compilers for 5 years after a replacement became available.
Once those 5 years have passed, new features from the new compiler can be used.

I'm updating the deprecation schedule (which I've not touched in too long) and several important features have become available.

Go through the codebase and use these features where they make sense:

• concepts
• constinit
• bit operations
• std::bit_cast
• [[nodiscard]]
• std::source_location
• std::shift_*
• std::assume_aligned()
• modules
• coroutines
• ranges