GN comment spelling fix.

tools/gn/builder.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/builder.h"
 
 #include "tools/gn/config.h"
 #include "tools/gn/deps_iterator.h"
 #include "tools/gn/err.h"
 #include "tools/gn/loader.h"
@@ skipping 224 matching lines @@
 
   return true;
 }
 
 bool Builder::ConfigDefined(BuilderRecord* record, Err* err) {
   Config* config = record->item()->AsConfig();
   if (!AddDeps(record, config->configs(), err))
     return false;
 
   // Make sure all deps of this config are scheduled to be loaded. For other
-  // item types like targets, the "should generate" flag is propogated around
+  // item types like targets, the "should generate" flag is propagated around
   // to mark whether this should happen. We could call
   // RecursiveSetShouldGenerate to do this step here, but since configs nor
   // anything they depend on is actually written, the "generate" flag isn't
   // relevant and means extra book keeping. Just force load any deps of this
   // config.
   for (const auto& cur : record->all_deps())
     ScheduleItemLoadIfNecessary(cur);
 
   return true;
 }
@@ skipping 279 matching lines @@
   std::string ret;
   for (size_t i = 0; i < cycle.size(); i++) {
     ret += "  " + cycle[i]->label().GetUserVisibleName(false);
     if (i != cycle.size() - 1)
       ret += " ->";
     ret += "\n";
   }
 
   return ret;
 }