Updated comment

regex/compile.go

@@ -1000,7 +1000,7 @@ func thompson(re []postfixNode) (Reg, error) {
 			s2 := mustPop(&nfa)
 			// Relax the requirements for concatenation a little bit - If
 			// the second element is not found ie. the postfixNodes look
-			// like 'a~', then that's fine, we just skip the concatenation.
+			// like 'a'+CONCAT, then that's fine, we just skip the concatenation.
 			s1, err := pop(&nfa)
 			if err != nil {
 				nfa = append(nfa, s2)