Fix help and error messages.

tools/gn/command_args.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 <map>
 
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "tools/gn/commands.h"
 #include "tools/gn/input_file.h"
@@ skipping 88 matching lines @@
 
 }  // namespace
 
 extern const char kArgs[] = "args";
 extern const char kArgs_HelpShort[] =
     "args: Display configurable arguments declared by the build.";
 extern const char kArgs_Help[] =
     "gn args [arg name]\n"
     "  Displays all arguments declared by buildfiles along with their\n"
     "  description. Build arguments are anything in a declare_args() block\n"
-    "  in any buildfile. The comment preceeding the declaration will be\n"
+    "  in any buildfile. The comment preceding the declaration will be\n"
     "  displayed here (so comment well!).\n"
     "\n"
-    "  These arguments can be overriden on the command-line:\n"
+    "  These arguments can be overridden on the command-line:\n"
     "    --args=\"doom_melon_setting=5 component_build=1\"\n"
     "  or in a toolchain definition (see \"gn help buildargs\" for more on\n"
     "  how this all works).\n"
     "\n"
     "  If \"arg name\" is specified, only the information for that argument\n"
     "  will be displayed. Otherwise all arguments will be displayed.\n";
 
 int RunArgs(const std::vector<std::string>& args) {
   Setup* setup = new Setup;
   setup->set_check_for_bad_items(false);
   if (!setup->DoSetup() || !setup->Run())
     return 1;
 
   const Scope::KeyValueMap& build_args =
       setup->build_settings().build_args().declared_arguments();
 
   if (args.size() == 1) {
     // Get help on a specific command.
     Scope::KeyValueMap::const_iterator found_arg = build_args.find(args[0]);
     if (found_arg == build_args.end()) {
-      Err(Location(), "Unknown build arg.",
+      Err(Location(), "Unknown build argument.",
           "You asked for \"" + args[0] + "\" which I didn't find in any "
           "buildfile\nassociated with this build.");
       return 1;
     }
     PrintArgHelp(args[0], found_arg->second);
     return 0;
   } else if (args.size() > 1) {
     // Too many arguments.
     Err(Location(), "You're holding it wrong.",
         "Usage: \"gn args [arg name]\"").PrintToStdout();
     return 1;
   }
 
   // List all arguments. First put them in a regular map so they're sorted.
   std::map<base::StringPiece, Value> sorted_args;
   for (Scope::KeyValueMap::const_iterator i = build_args.begin();
        i != build_args.end(); ++i)
     sorted_args.insert(*i);
 
   for (std::map<base::StringPiece, Value>::iterator i = sorted_args.begin();
        i != sorted_args.end(); ++i) {
     PrintArgHelp(i->first, i->second);
     OutputString("\n");
   }
 
   return 0;
 }
 
 }  // namespace commands