Fix grammar

Author: Girgias

tests/lang/short_tags_unique_deprecation_notice.phpt

@@ -2,7 +2,7 @@
 Unique PHP short tag deprecation with multiple short tags used
 --FILE--
 <?php
- echo "Used a normal tags\n";
+ echo "Used a normal tag\n";
 ?>
 <?
  echo "Used a short tag\n";