search-select: support opening multiple files

[tomocafe]

search-select 1 2 3

should open matches 1, 2, and 3, to the correct line numbers, in separate editor buffers/windows/etc.

[tomocafe]

Need to come up with UI for this. How to handle actions? (e.g. cmd file1 file2 or cmd file1; cmd file2)

How to deal with editor-specific methods of opening multiple files?