Fix typographical error in comment in r4056

src/ast.h

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 223 matching lines @@
   // AST analysis results
 
   // True if the expression rooted at this node can be compiled by the
   // side-effect free compiler.
   bool side_effect_free() { return SideEffectFreeField::decode(bitfields_); }
   void set_side_effect_free(bool is_side_effect_free) {
     bitfields_ &= ~SideEffectFreeField::mask();
     bitfields_ |= SideEffectFreeField::encode(is_side_effect_free);
   }
 
-  // Will ToInt32 ECMA 262-3 9.5) or ToUunt32 (ECMA 262-3 9.6)
+  // Will ToInt32 (ECMA 262-3 9.5) or ToUint32 (ECMA 262-3 9.6)
   // be applied to the value of this expression?
   // If so, we may be able to optimize the calculation of the value.
   bool to_int32() { return ToInt32Field::decode(bitfields_); }
   void set_to_int32(bool to_int32) {
     bitfields_ &= ~ToInt32Field::mask();
     bitfields_ |= ToInt32Field::encode(to_int32);
   }
 
 
  private:
@@ skipping 1619 matching lines @@
 #undef DEF_VISIT
 
  private:
   bool stack_overflow_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_