feature: Snacks.picker - Open all selected in splits

[rijulkap]

Did you check the docs?

• [x] I have read all the snacks.nvim docs

Is your feature request related to a problem? Please describe.

Snacks.picker allows you to select multiple items when active. Was wondering if it'd be possible to open all selected items simultaneously in splits, akin to fzf-lua? As of currently, selecting multiple and using the default / key opens a single split with the last item selected, with the rest open as separate buffers.

Describe the solution you'd like

The ability to open all selected items as splits, simultaneously. Eg: Selecting 4 items should split the tab into 5 windows (1 currently open + 4 selected)

Describe alternatives you've considered

Fzf-lua allows you to do this by default.

Additional context

No response