update-compiler-support/include/gsl/gsl_algorithm

#pragma once
#pragma message(                                                                                   \
    "This header will soon be removed. Use <gsl/algorithm> instead of <gsl/gsl_algorithm>")
#include <gsl/algorithm>
renaming main logic files. Added warning message of the removal and include passthrough. Renamed includes in the source files. Ran Clang-Format (#946 ) 2020-10-29 17:38:48 -07:00			`#pragma once`
gsl::at behavior change regarding gsl::span (#985 ) 2021-05-20 18:18:08 -07:00			`#pragma message( \`
			`"This header will soon be removed. Use <gsl/algorithm> instead of <gsl/gsl_algorithm>")`
renaming main logic files. Added warning message of the removal and include passthrough. Renamed includes in the source files. Ran Clang-Format (#946 ) 2020-10-29 17:38:48 -07:00			`#include <gsl/algorithm>`