GN docs: update the example of declare_args().

tools/gn/functions.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/functions.h"
 
 #include <stddef.h>
 #include <iostream>
 #include <utility>
 
@@ skipping 411 matching lines @@
         }
 
 Example
 
   declare_args() {
     enable_teleporter = true
     enable_doom_melon = false
   }
 
   If you want to override the (default disabled) Doom Melon:
-    gn --args="enable_doom_melon=true enable_teleporter=false"
+    gn --args="enable_doom_melon=true enable_teleporter=true"
   This also sets the teleporter, but it's already defaulted to on so it will
   have no effect.
 )";
 
 Value RunDeclareArgs(Scope* scope,
                      const FunctionCallNode* function,
                      const std::vector<Value>& args,
                      BlockNode* block,
                      Err* err) {
   NonNestableBlock non_nestable(scope, function, "declare_args");
@@ skipping 694 matching lines @@
   }
 
   // Otherwise it's a no-block function.
   if (!VerifyNoBlockForFunctionCall(function, block, err))
     return Value();
   return found_function->second.no_block_runner(scope, function,
                                                 args.list_value(), err);
 }
 
 }  // namespace functions