[sway/scratchpad] New module for scratchpad of sway

[asas1asas200]

Scratchpad indicator for swaywm.

Related issue: #1662 .

[ErikReider]

Does this show each application icon just like the wlr/taskbar module or just the count?

[asas1asas200]

I only put them in the tooltip, it will show when the cursor hovered. It shows too much information if displays all apps. If you want to see all the scratchpad apps on the bar I can write like systray show only app icon on that, what do you think?

[ErikReider]

Yeah. An option for displaying the app icons sounds good! :)

Clicking the icons to raise the application would also be a cool addition

[Alexays]

LGTM :)