Make stray 'return' an early error

src/preparser.cc

Index: src/preparser.cc
diff --git a/src/preparser.cc b/src/preparser.cc
index a6811e9b9713e025ca7ea975ab710f268c510511..21e2b7786f3fd84e2e6eac3542e6bbdf4b1c3bdc 100644
--- a/src/preparser.cc
+++ b/src/preparser.cc
@@ -582,7 +582,7 @@ PreParser::Statement PreParser::ParseReturnStatement(bool* ok) {
   // ReturnStatement ::
   //   'return' [no line terminator] Expression? ';'
 
-  // Consume the return token. It is necessary to do the before
+  // Consume the return token. It is necessary to do before
   // reporting any errors on it, because of the way errors are
   // reported (underlining).
   Expect(Token::RETURN, CHECK_OK);