This only changs the clang-format file and adds documentation
referring to the new process for formatting code. A future commit
will perform a reformatting according to these new formatting
settings.
Original-commit: flang-compiler/f18@02531d788e
Reviewed-on: https://github.com/flang-compiler/f18/pull/945
Updated CMake files accordingly, using better regex
Updated license headers to match new extension and fit within 80 columns
Updated other comments within files that referred to the old extension
Original-commit: flang-compiler/f18@ae7721e611
Reviewed-on: https://github.com/flang-compiler/f18/pull/958