Merge branch 'rr/completion-branch-config'

Two-level configuration variable names in "branch.*" and "remote.*" hierarchies whose variables are predominantly three-level where not completed by hitting a <TAB> in bash and zsh completions. * rr/completion-branch-config: completion: fix remote.pushdefault completion: fix branch.autosetup(merge|rebase) completion: introduce __gitcomp_nl_append () zsh completion: find matching custom bash completion