regcomp.c: Typo, spacing in comment

regcomp.c

@@ -15163,7 +15163,7 @@ S_handle_regex_sets(pTHX_ RExC_state_t *pRExC_state, SV** return_invlist,
                     vFAIL("Unexpected ')'");
                 }
 
-                 /* If at least two thing on the stack, treat this as an
+                /* If at least two things on the stack, treat this as an
                   * operator */
                 if (top_index - fence >= 1) {
                     goto join_operators;