Replace shell_pipe_to with shell_pipe_popup

[gustafla]

The new shell_pipe_popup performs a similar function but also allows the user to see the output in an automatically closing popup.

I know this #1682 is similar, but I want selection piping and quick output feedback for running word counts.

[gustafla]

I would otherwise maybe keep the output-ignoring variant of shell_pipe, but I couldn't find a reasonable working key mapping.

[the-mikedavis]

I think it'd be good to keep shell_pipe_to around. It doesn't necessarily need a default keybinding, but having the command available lets people remap to it if they want, like

[keys.normal]
"|" = "shell_pipe_to"

[gustafla]

I agree, my bad, didn't think about that I can just keep it there. Fixed.

[gustafla]

Actually, I'd personally find this feature more useful if it joined all selections with spaces or newlines before piping to a single shell command. The current implementation runs n commands for n selections and shows n results in a popup.

[archseer]

I'd personally prefer the default keybinding and offer this as an alternative

[pascalkuthe]

closing this one out as stale. Thank you for contributing!