The `selectOnClose` option did not work in production because we
were decorating the `dropdownAdapter` instead of the `resultsAdpater`
when automatically generating the adapters. This has now been fixed,
and the option should work without errors in production.
This also adds documentation for the `selectOnClose` option.
This closes https://github.com/select2/select2/issues/2953.
80bda0ad55