remove trailing whitespace;

Author: coke

doc/Language/regexes.pod6

@@ -993,7 +993,7 @@ So C<'a' ~~ /A/> is false, but C<'a' ~~ /:i A/> is a successful match.
 Regex adverbs can come before or inside a regex declaration and only affect
 the part of the regex that comes afterwards, lexically.
 Note that regex adverbs appearing before the regex must appear after
-something that introduces the regex to the parser, like 'rx' or 'm' or a bare '/'. 
+something that introduces the regex to the parser, like 'rx' or 'm' or a bare '/'.
 This is NOT valid:
 
     =begin code :skip-test