(clear_regexp_cache): Fix a typo in a comment.

src/search.c

@@ -209,8 +209,8 @@ clear_regexp_cache ()
   int i;
 
   for (i = 0; i < REGEXP_CACHE_SIZE; ++i)
-    /* It's tempting to compare with the syntax-table we've actually changd,
-       but it's not sufficient because char-table inheritance mewans that
+    /* It's tempting to compare with the syntax-table we've actually changed,
+       but it's not sufficient because char-table inheritance means that
        modifying one syntax-table can change others at the same time.  */
     if (!EQ (searchbufs[i].syntax_table, Qt))
       searchbufs[i].regexp = Qnil;