[torque] Add '\n' handling in Torque strings

This CL adds the newline character as a valid character
in Torque strings.

You can now write Print('Hello, World!\n') in Torque and it works!

Change-Id: I2a1f87cfef492fedd3d24086e226d3ebaf882115
Reviewed-on: https://chromium-review.googlesource.com/1118229Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Théotime Grohens <theotime@google.com>
Cr-Commit-Position: refs/heads/master@{#54089}

src/torque/Torque.g4

@@ -81,7 +81,7 @@ NOT: '!';
 
 STRING_LITERAL : ('"' ( ESCAPE | ~('"' | '\\' | '\n' | '\r') ) * '"')
                | ('\'' ( ESCAPE | ~('\'' | '\\' | '\n' | '\r') ) * '\'');
-fragment ESCAPE : '\\' ( '\'' | '\\' | '"' );
+fragment ESCAPE : '\\' ( '\'' | '\\' | '"' | 'n' | 'r' );
 
 IDENTIFIER  :   [A-Za-z][0-9A-Za-z_]* ;
 

test/torque/test-torque.tq

@@ -219,4 +219,8 @@ module test {
     check(someVeryLongVariableNameThatWillCauseLineBreaks > 0
            && someVeryLongVariableNameThatWillCauseLineBreaks < 10);
   }
+
+  macro TestNewlineInString() {
+    Print('Hello, World!\n');
+  }
 }