Merge branch 'tz/branch-doc-remove-set-upstream'

"git branch --set-upstream" has been deprecated and (sort of) removed, as "--set-upstream-to" is the preferred one these days. The documentation still had "--set-upstream" listed on its synopsys section, which has been corrected. * tz/branch-doc-remove-set-upstream: branch doc: remove --set-upstream from synopsis