Support instantly taking screenshot before choosing portion with slurp

[AndreasBackx]

I often want to take a screenshot from a popup window, whether it be in the browser or elsewhere. Unfortunately these popups close when focus is lost. MacOS takes a screenshot when the screenshot button is pressed and the selection tool then allows you to select a portion of the screen thus allowing you to take screenshot of popups.

Having this functionality in Wayshot would not be trivial as it would require creating an overlay on which slurp can then be used. Currently slurp is also run before Wayshot so we cannot take a screenshot and show it as a moment capture before running slurp so that needs to be changed as well. We could make --slurp accept any command and run it from inside of the CLI so we can take a screenshot first and show it to the user after which we can run slurp to select what thay want and then we'd only need to do a crop. What do you think?