Fix spelling errors in comments

boost/functional/forward_adapter.hpp

@@ -144,8 +144,8 @@ namespace boost
             : boost::result_of< BOOST_DEDUCED_TYPENAME c<Self>::t() >
         { };
 
-        // WHen operator()() doesn't have any parameters, it can't
-        // be templatized and can't use SFINAE, so intead use class
+        // When operator()() doesn't have any parameters, it can't
+        // be templatized and can't use SFINAE, so instead use class
         // template parameter SFINAE to decide whether to instantiate it.
 
         template <typename T, typename R = void>

boost/functional/lightweight_forward_adapter.hpp

@@ -150,7 +150,7 @@ namespace boost
         { };
 
         // When operator() doesn't have any parameters, it can't
-        // be templatized and can't use SFINAE, so intead use class
+        // be templatized and can't use SFINAE, so instead use class
         // template parameter SFINAE to decide whether to instantiate it.
 
         template <typename T, typename R = void>

boost/python/object/function_handle.hpp

@@ -31,7 +31,7 @@ inline handle<> function_handle(F const& f, Signature)
     );
 }
 
-// Just like make_function, but returns a handle<> intead. Same
+// Just like make_function, but returns a handle<> instead. Same
 // reasoning as above.
 template <class F>
 handle<> make_function_handle(F f)