Update porter handbook: Quarterly and Latest Ports Branches

[rodrigo]

Summary

By default, the pkg ports repo is now "FreeBSD-ports".

[rodrigo]

Fix was done in the english version of the handbook
but not in the russian one

[bcr]

You don't need to update the languages beside the english original. The translation teams will sync the changes from the en version and then update if necessary. For code instruction changes (like yours), they get applied without the need for a change.

[rodrigo]

I leave the changes to the translation team :)

[bcr]

Adding some more reviewers for comments...