diagnostics: move diagnostic_metadata to diagnostics::metadata

diagnostics: move diagnostic_metadata to diagnostics::metadata

renamed: gcc/diagnostic-metadata.h -> gcc/diagnostics/metadata.h

No functional change intended.

gcc/analyzer/ChangeLog:
	* diagnostic-manager.cc: Update for move of diagnostic_metadata to
	diagnostics::metadata.
	* kf.cc: Likewise.
	* pending-diagnostic.h: Likewise; also, update #include for move
	of "diagnostic-metadata.h" to "diagnostics/metadata.h".

gcc/cobol/ChangeLog:
	* util.cc: Remove redundant #includes

gcc/ChangeLog:
	* diagnostic-core.h: Update for move of diagnostic_metadata to
	diagnostics::metadata.
	* diagnostic-format-html.cc: Likewise; also, update #include for
	move of "diagnostic-metadata.h" to "diagnostics/metadata.h".
	* diagnostic-format-sarif.cc: Likewise.
	* diagnostic-format-text.cc: Likewise.
	* diagnostic-global-context.cc: Likewise.
	* diagnostic.cc: Likewise.
	* diagnostic.h: Likewise.
	* diagnostic-metadata.h: Move to...
	* diagnostics/metadata.h: ...here, updating header guard.
	(class diagnostic_metadata): Move to...
	(class diagnostics::metadata): ...here.  Drop redundant
	"diagnostics::" qualifiers.
	* libgdiagnostics.cc: : Update #include for move of
	"diagnostic-metadata.h" to "diagnostics/metadata.h", and update
	for move of diagnostic_metadata to diagnostics::metadata.
	* selftest-diagnostic.cc: Update for move of diagnostic_metadata
	to diagnostics::metadata.
	* selftest-diagnostic.h: Likewise.

gcc/rust/ChangeLog:
	* rust-diagnostics.cc: Update #include for move of
	"diagnostic-metadata.h" to "diagnostics/metadata.h", and update
	for move of diagnostic_metadata to diagnostics::metadata.

gcc/testsuite/ChangeLog:
	* gcc.dg/plugin/analyzer_cpython_plugin.cc: : Update #include for
	move of "diagnostic-metadata.h" to "diagnostics/metadata.h"
	* gcc.dg/plugin/analyzer_kernel_plugin.cc: Likewise.
	* gcc.dg/plugin/analyzer_known_fns_plugin.cc: Likewise.
	* gcc.dg/plugin/diagnostic_plugin_test_graphs.cc: Likewise.  Also
	update for move of diagnostic_metadata to diagnostics::metadata.
	* gcc.dg/plugin/diagnostic_plugin_test_metadata.cc: Likewise.
	* gcc.dg/plugin/diagnostic_plugin_test_paths.cc: Likewise.

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