Allow creation and modification of scopes in GN.

tools/gn/command_help.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 <algorithm>
 #include <iostream>
 
 #include "base/command_line.h"
 #include "tools/gn/args.h"
 #include "tools/gn/commands.h"
@@ skipping 44 matching lines @@
   // Target variables.
   OutputString("\nVariables you set in targets (type \"gn help <variable>\" "
                "for more details):\n");
   for (const auto& target : variables::GetTargetVariables())
     PrintShortHelp(target.second.help_short);
 
   OutputString("\nOther help topics:\n");
   PrintShortHelp("all: Print all the help at once");
   PrintShortHelp("buildargs: How build arguments work.");
   PrintShortHelp("dotfile: Info about the toplevel .gn file.");
-  PrintShortHelp("grammar: Formal grammar for GN build files.");
+  PrintShortHelp("grammar: Language and grammar for GN build files.");
   PrintShortHelp(
       "input_conversion: Processing input from exec_script and read_file.");
   PrintShortHelp("label_pattern: Matching more than one label.");
   PrintShortHelp("nogncheck: Annotating includes for checking.");
   PrintShortHelp("runtime_deps: How runtime dependency computation works.");
   PrintShortHelp("source_expansion: Map sources to outputs for scripts.");
   PrintShortHelp("switches: Show available command-line switches.");
 }
 
 void PrintSwitchHelp() {
@@ skipping 191 matching lines @@
     OutputString("Run `gn help` for a list of available topics.\n",
                  DECORATION_NONE);
   } else {
     OutputString("Did you mean `gn help " + suggestion.as_string() + "`?\n",
                  DECORATION_NONE);
   }
   return 1;
 }
 
 }  // namespace commands