add ability to write new value if it not found in list

[pbelskiy]

First of all thanks for this great plugin!

Is your feature request related to a problem? Please describe. In some cases of usage your plugin I wanna write some custom value if it not found in original list, and submit it to server.

Describe the solution you'd like When no item is found I suggest to add it to list by pressing enter button.

Describe alternatives you've considered I've create some hack in your plugin, but it's incorrect, so could you add this future, please.

Additional context No