Fix help and error messages.

tools/gn/variables.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "tools/gn/variables.h"
 
 namespace variables {
 
 // Built-in variables ----------------------------------------------------------
 
@@ skipping 724 matching lines @@
     "  not possible for Ninja to know about this dependency.\n"
     "\n"
     "  Source prerequisites solves this problem by declaring such\n"
     "  dependencies. It will introduce a Ninja \"implicit\" dependency for\n"
     "  each source file in the target on the listed files.\n"
     "\n"
     "  For binary targets, the files in the \"source_prereqs\" should all be\n"
     "  listed in the \"outputs\" section of another target. There is no\n"
     "  reason to declare static source files as source prerequisites since\n"
     "  the normal include file dependency management will handle them more\n"
-    "  efficiently anwyay.\n"
+    "  efficiently anyway.\n"
     "\n"
     "  For custom script targets that don't generate \".d\" files, the\n"
     "  \"source_prereqs\" section is how you can list known compile-time\n"
     "  dependencies your script may have.\n"
     "\n"
     "  See also \"gn help data\" and \"gn help datadeps\" (which declare\n"
     "  run-time rather than compile-time dependencies), and\n"
     "  \"gn help hard_dep\" which allows you to declare the source dependency\n"
     "  on the target generating a file rather than the target consuming it.\n"
     "\n"
@@ skipping 81 matching lines @@
     INSERT_VARIABLE(Script)
     INSERT_VARIABLE(SourcePrereqs)
     INSERT_VARIABLE(Sources)
   }
   return info_map;
 }
 
 #undef INSERT_VARIABLE
 
 }  // namespace variables