[re.regiter.general] Move const into \tcode (#7878)

Author: Andreas-Krug

source/text.tex

@@ -12238,8 +12238,8 @@
 constructs an end-of-sequence iterator object,
 which is the only legitimate iterator to be used for the end
 condition. The result of \tcode{operator*} on an end-of-sequence iterator is not
-defined. For any other iterator value a const
-\tcode{match_results<BidirectionalIterator>\&} is returned. The result of
+defined. For any other iterator value a
+\tcode{const match_results<BidirectionalIterator>\&} is returned. The result of
 \tcode{operator->} on an end-of-sequence iterator is not defined. For any other
 iterator value a \tcode{const match_results<BidirectionalIterator>*} is
 returned. It is impossible to store things into \tcode{regex_iterator}s. Two