Bootstrap grip columns are configurable. A default on the form and, if necessary, per formelement. The default is now changed from 2,6,4 to 2,9,1
UsersManual/index.rst: updated to the new behaviour.
Support.php: setIfNotSet() has a new third parameter.
AbstractBuildForm.php, BuildFormBootstrap.php, BuildFormPlain.php, BuildFormPlain.php, QuickFormQuery.php: New abstract function fillWrapLabelInputNote().