Support passing funcrefs to textobj#user#select and textobj#user#move?

[fsouza]

Thank you very much for building this plugin, it's really cool :)

I was wondering if you'd be willing to take a PR enabling users to pass actual functions instead of function names? This way, users can pass lambdas, or for the case I'm actually interested in, pass a lua function (enabled by vim/vim#6246 and neovim/neovim#12507).

Thanks again!