Update comments for globally unique extension number for custom options.
Update comments for globally unique extension number for custom options.


git-svn-id: 6df6fa3ddd728f578ea1442598151d5900a6ed44@394 630680e5-0e50-0410-840e-4b1c322b438d

GreatFruitOmsk/protobuf-py3,spilgames/protobuf,mkrautz/external-protobuf,svn2github/protobuf-mirror,kastnerkyle/protobuf-py3,datacratic/protobuf,mpapierski/protobuf,svn2github/protobuf-mirror,patrickhartling/protobuf,svn2github/google-protobuf,datacratic/protobuf,machinalis/protobuf-python3,GreatFruitOmsk/protobuf-py3,da2ce7/protobuf,mkrautz/external-protobuf,beyang/protobuf,chandlerc/protobuf-llvm,Distrotech/protobuf,svn2github/google-protobuf,spilgames/protobuf,GreatFruitOmsk/protobuf-py3,beyang/protobuf,lcy03406/protobuf,datacratic/protobuf,kastnerkyle/protobuf-py3,GreatFruitOmsk/protobuf-py3,da2ce7/protobuf,aidansteele/protobuf-mirror,mikelikespie/protobuf,lcy03406/protobuf,machinalis/protobuf-python3,mkrautz/external-protobuf,svn2github/protobuf-mirror,svn2github/google-protobuf,aidansteele/protobuf-mirror,mikelikespie/protobuf,mkrautz/external-protobuf,patrickhartling/protobuf,mikelikespie/protobuf,kastnerkyle/protobuf-py3,beyang/protobuf,machinalis/protobuf-python3,Distrotech/protobuf,da2ce7/protobuf,svn2github/google-protobuf,svn2github/protobuf-mirror,beyang/protobuf,beyang/protobuf,patrickhartling/protobuf,aidansteele/protobuf-mirror,datacratic/protobuf,da2ce7/protobuf,svn2github/google-protobuf,chandlerc/protobuf-llvm,mpapierski/protobuf,lcy03406/protobuf,kastnerkyle/protobuf-py3,datacratic/protobuf,chandlerc/protobuf-llvm,mikelikespie/protobuf,Distrotech/protobuf,mikelikespie/protobuf,lcy03406/protobuf,patrickhartling/protobuf,Distrotech/protobuf,GreatFruitOmsk/protobuf-py3,lcy03406/protobuf,Distrotech/protobuf,mpapierski/protobuf,mpapierski/protobuf,spilgames/protobuf,chandlerc/protobuf-llvm,da2ce7/protobuf,machinalis/protobuf-python3,patrickhartling/protobuf,mpapierski/protobuf,kastnerkyle/protobuf-py3,aidansteele/protobuf-mirror,aidansteele/protobuf-mirror,chandlerc/protobuf-llvm,svn2github/protobuf-mirror,spilgames/protobuf,spilgames/protobuf,mkrautz/external-protobuf