fix: over-permissive regex for added/deleted file meta header

The previous pattern uselessly included `.*`, unlike all the other
patterns, and so would erroneously match on actual diff content lines.

Noticed this because the line itself was filtered out of diffs in this
codebase.

This also tightens the pattern since the file mode will always be six
octal (0-7) chars; and in the git codebase the format string is:
  "%s%snew file mode %06o%s\n"

Author: rwe

diff-so-fancy

@@ -303,7 +303,7 @@ sub do_dsf_stuff {
 		###################################
 		# Remove any new file permissions #
 		###################################
-		} elsif ($remove_file_add_header && $line =~ /^${ansi_color_regex}.*new file mode/) {
+		} elsif ($remove_file_add_header && $line =~ /^${ansi_color_regex}new file mode [0-7]{6}/) {
 			# Don't print the line (i.e. remove it from the output);
 			$last_file_mode = "add";
 			if ($patch_mode) {
@@ -312,7 +312,7 @@ sub do_dsf_stuff {
 		######################################
 		# Remove any delete file permissions #
 		######################################
-		} elsif ($remove_file_delete_header && $line =~ /^${ansi_color_regex}deleted file mode/) {
+		} elsif ($remove_file_delete_header && $line =~ /^${ansi_color_regex}deleted file mode [0-7]{6}/) {
 			# Don't print the line (i.e. remove it from the output);
 			$last_file_mode = "delete";
 			if ($patch_mode) {