Add closeOnSelect option

I would love the the option to make the picker window close automatically as soon as a color is chosen. Changing input colors would then be just two mouse clicks instead of three!

The issue does not name a file or test. Start by locating the picker’s color-selection handling and its existing option configuration, then trace when the picker window closes. Done means a closeOnSelect option closes the picker after choosing a color while preserving the current behavior when the option is disabled.

Written by the indexing model from the issue text.