patch: delete dead -x option (#699)

* The -x (aka --debug) option exists in the GNU version of patch, but the perl version never did anything with -x
* Mentioning -x in the pod manual makes the useful information more difficult to find
* This option is not covered by the standard so removing it is not a compatibility issue [1]
* Debugging the perl version can be as simple as setting a breakpoint in Patch::apply() or Patch::Ed::apply()

1. https://pubs.opengroup.org/onlinepubs/007904975/utilities/patch.html

Author: mknos

bin/patch

@@ -52,7 +52,7 @@ if (@ARGV) {
         directory|d=s           normal|n                unified|u
         ifdef|D=s               forward|N               version|v
         ed|e                    output|o=s              version-control|V=s
-        remove-empty-files|E    strip|p=i               debug|x=i
+        remove-empty-files|E    strip|p=i
     /;
 
     # Each patch may have its own set of options.  These are separated by
@@ -1476,13 +1476,6 @@ Always make simple backups.
 
 =back
 
-=item -xnumber or --debug number
-
-sets  internal  debugging  flags,
-and is of no interest to I<patch> patchers [see L<"note 8">].
-
-=back
-
 =head1 ENVIRONMENT
 
 B<SIMPLE_BACKUP_SUFFIX>
@@ -1621,10 +1614,6 @@ file is handy, GNU patch will attempt to get or check out the file.
 GNU patch requires a space between the B<-D> and the argument.  This has been
 made optional.
 
-=head2 note 8
-
-There are currently no debugging flags to go along with B<-x>.
-
 =head1 AUTHOR
 
 The Perl implementation of I<patch> was written by Tim Gim Yee,