Merge branch 'fc/push-simple-updates'

Some code and doc clarification around "git push". * fc/push-simple-updates: doc: push: explain default=simple correctly push: remove unused code in setup_push_upstream() push: simplify setup_push_simple() push: reorganize setup_push_simple() push: copy code to setup_push_simple() push: hedge code of default=simple push: rename !triangular to same_remote