Minor fixes to tools/gn.

tools/gn/substitution_writer.h

 // Copyright 2014 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.
 
 #ifndef TOOLS_GN_SUBSTITUTION_WRITER_H_
 #define TOOLS_GN_SUBSTITUTION_WRITER_H_
 
 #include <iosfwd>
 #include <vector>
 
@@ skipping 97 matching lines @@
       const SubstitutionList& list,
       const SourceFile& source,
       std::vector<std::string>* output);
   static void ApplyListToSourceAsOutputFile(
       const Settings* settings,
       const SubstitutionList& list,
       const SourceFile& source,
       std::vector<OutputFile>* output);
 
   // Like ApplyListToSource but applies the list to all sources and replaces
-  // rather than appesnds the output (this produces the complete output).
+  // rather than appends the output (this produces the complete output).
   static void ApplyListToSources(
       const Settings* settings,
       const SubstitutionList& list,
       const std::vector<SourceFile>& sources,
       std::vector<SourceFile>* output);
   static void ApplyListToSourcesAsString(
       const Settings* settings,
       const SubstitutionList& list,
       const std::vector<SourceFile>& sources,
       std::vector<std::string>* output);
@@ skipping 91 matching lines @@
   // Like GetSourceSubstitution but for strings based on the target or
   // toolchain. This type of result will always be relative to the build
   // directory.
   static std::string GetLinkerSubstitution(
       const Target* target,
       const Tool* tool,
       SubstitutionType type);
 };
 
 #endif  // TOOLS_GN_SUBSTITUTION_WRITER_H_