diagnostics: move gcc/diagnostic-color.{h,cc} to gcc/diagnostics/color.{h,cc}

diagnostics: move gcc/diagnostic-color.{h,cc} to gcc/diagnostics/color.{h,cc}

No functional change intended.

gcc/ChangeLog:
	* Makefile.in (OBJS-libcommon): Replace diagnostic-color.o with
	diagnostics/color.o.
	(PLUGIN_HEADERS): Remove diagnostic-color.h in favor of glob.
	* common.opt: Update for move of diagnostic-color.h to
	diagnostics/color.h.
	* diagnostic.cc: Likewise.
	* diagnostic-color.cc: Move to...
	* diagnostics/color.cc: ...here.
	* diagnostic-color.h: Move to...
	* diagnostics/color.h: ...here.
	* diagnostics/edit-context.cc: Update for move of
	diagnostic-color.h to diagnostics/color.h.
	* diagnostics/output-spec.cc: Likewise.
	* diagnostics/paths-output.cc: Likewise.
	* diagnostics/source-printing.cc: Likewise.
	* diagnostics/text-sink.cc: Likewise.
	* libgdiagnostics.cc: Likewise.
	* opts.cc: Likewise.
	* pretty-print-markup.h: Likewise.
	* pretty-print.cc: Likewise.
	* selftest-run-tests.cc: Likewise.
	* selftest.h: Likewise.
	* text-art/style.cc: Likewise.

gcc/cp/ChangeLog:
	* error.cc: Update for move of diagnostic-color.h to
	diagnostics/color.h.

gcc/fortran/ChangeLog:
	* error.cc: Update for move of diagnostic-color.h to
	diagnostics/color.h.

gcc/m2/ChangeLog:
	* gm2-gcc/m2color.cc: Update for move of diagnostic-color.h to
	diagnostics/color.h.

gcc/testsuite/ChangeLog:
	* gcc.dg/plugin/analyzer_cpython_plugin.cc: Update for move of
	diagnostic-color.h to diagnostics/color.h.
	* gcc.dg/plugin/analyzer_kernel_plugin.cc: Likewise.
	* gcc.dg/plugin/analyzer_known_fns_plugin.cc: Likewise.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>