Fix collate.linux.utf8 expected output for recent error message change.

Noted by Jeff Davis.

src/test/regress/expected/collate.linux.utf8.out

@@ -967,6 +967,7 @@ CREATE COLLATION test3 (lc_collate = 'en_US.utf8'); -- fail, need lc_ctype
 ERROR:  parameter "lc_ctype" must be specified
 CREATE COLLATION testx (locale = 'nonsense'); -- fail
 ERROR:  could not create locale "nonsense": No such file or directory
+DETAIL:  The operating system could not find any locale data for the locale name "nonsense".
 CREATE COLLATION test4 FROM nonsense;
 ERROR:  collation "nonsense" for encoding "UTF8" does not exist
 CREATE COLLATION test5 FROM test0;