Include file name in SyntaxError message if present

FIX: Mention the source file name in syntax error messages when given.

Author: Norbiros

acorn/src/location.js

@@ -12,6 +12,9 @@ const pp = Parser.prototype
 pp.raise = function(pos, message) {
   let loc = getLineInfo(this.input, pos)
   message += " (" + loc.line + ":" + loc.column + ")"
+  if (this.sourceFile) {
+    message += " in " + this.sourceFile
+  }
   let err = new SyntaxError(message)
   err.pos = pos; err.loc = loc; err.raisedAt = this.pos
   throw err