Fix a bunch of spelling mistakes :\

src/jsregexp.h

 // Copyright 2006-2008 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 635 matching lines @@
 
   // Returns a sibling of this node whose interests match the ones in
   // the given node info.  The info must not contain any assertions.
   // If no node exists a new one will be created by cloning the current
   // node.  The result will always be an instance of the same concrete
   // class as this node.
   RegExpNode* EnsureSibling(NodeInfo* info, bool* cloned);
 
   // Returns a clone of this node initialized using the copy constructor
   // of its concrete class.  Note that the node may have to be pre-
-  // processed before it is on a useable state.
+  // processed before it is on a usable state.
   virtual RegExpNode* Clone() = 0;
 
  private:
   Label label_;
   NodeInfo info_;
   SiblingList siblings_;
   int variants_generated_;
 };
 
 
@@ skipping 557 matching lines @@
                                     Handle<String> pattern,
                                     bool is_ascii);
 
   static void DotPrint(const char* label, RegExpNode* node, bool ignore_case);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_JSREGEXP_H_