This is enabled by the C++20 __VA_OPT__ feature.
Uses of "{}" format string were updated.
Some warning suppressions were required for older clang versions.
Also improve codegen of wpi::Logger::Log(), frc::ReportError(), and frc::MakeError();
these generate better and less redundant code if they use fmt::string_view for the
format string instead of templating on it.
This makes code easier to read and more consistent between C++ and Java.
Also update clang-format settings to always add a line break (even if no braces are used).
A templated hal::Handle class is used to wrap handles to make them move-only.
This eliminates a lot of boilerplate move constructor/assignment code
in the main WPILib classes. HAL_SPIPort and HAL_I2CPort are also wrapped.
The wrapper class does not implement destruction. This would require the
wrapper class to be handle-specific (rather than generic) and would result
in more code added than it removed, plus would add header dependencies on
more HAL headers. In addition, some HAL handle release functions are more
complex (e.g. have return values) and can't be easily mapped to a destructor.
The old headers were moved into folders because doing so avoids polluting
the system include directories.
Folder names were also normalized to lowercase.
