Merge branch 'nd/completion-more-parameters'

The command line completion (in contrib/) has been taught to
complete more subcommand parameters.

* nd/completion-more-parameters:
completion: add more parameter value completion

diff --cc builtin/am.c
Simple merge

diff --cc builtin/commit.c
Simple merge

diff --cc contrib/completion/git-completion.bash
Simple merge

diff --cc diff.c
Simple merge

diff --cc merge-recursive.c
Simple merge

diff --cc pretty.c
Simple merge

diff --cc ref-filter.c
Simple merge

diff --cc submodule.c
Simple merge