Add a --source-comment=<text> option to objdump which provides a prefix to dipslayed...

Add a --source-comment=<text> option to objdump which provides a prefix to dipslayed source code lines.

	PR 24931
	* objdump.c (source_comment): New static variable.
	(option_values): Add OPTION_SOURCE_COMMENT.
	(long_opions): Add --source-comment.
	(print_line): If source comment is set, use it as a prefix to the
	source code line.
	(main): Handle OPTION_SOURCE_COMMENT.
	* doc/binutils.texi: Document the new option.
	* NEWS: Mention the new feature.
	* testsuite/binutils-all/objdump.exp (test_objdump_S): Add tests
	of the -S and --source-comment options.