Merge branch 'bc/submodule-status-ignored'

* bc/submodule-status-ignored:
Improve documentation concerning the status.submodulesummary setting
submodule: don't print status output with ignore=all
submodule: fix confusing variable name

diff --cc Documentation/config.txt
Simple merge

diff --cc git-submodule.sh
Simple merge

diff --cc t/t7401-submodule-summary.sh
Simple merge

diff --cc t/t7508-status.sh
Simple merge