"git remote rename X Y" needs to adjust configuration variables
(e.g. branch.<name>.remote) whose value used to be X to Y.
branch.<name>.pushRemote is now also updated.
* bw/remote-rename-update-config:
remote rename/remove: gently handle remote.pushDefault config
config: provide access to the current line number
remote rename/remove: handle branch.<name>.pushRemote config values
remote: clean-up config callback
remote: clean-up by returning early to avoid one indentation
pull --rebase/remote rename: document and honor single-letter abbreviations rebase types