Custom xdg-protocol integration.

[migonos0]

I'm not sure if this non expected behavior has something to do with "zap" or is an issue of the AppImage I'm trying to install but either way ill describe the issue in case it can help improve zap or anyone else's experience.

1. Common description:
   The AppImage I'm installing needs to register an xdg-protocol. "zap" does it correctly by adding MimeType=x-scheme-handler/pie;x-scheme-handler/pie; to the .desktop file under ~/.local/share/applications. However the app won't use the protocol, in order to fix this issue I:
   1. Remove the duplicated entry so the file remains like this: MimeType=x-scheme-handler/pie;.
   2. Add the following line to "mimeapps.list" file:

   [Default Applications]
   x-scheme-handler/pie=http-desktop.desktop
   

   3. Launch and use the application as expected.
2. Runtime environment information:
   1. OS: Arch Linux.
   2. ZAP Version: Zap version Build:v2.2.1.1.gb8ed330 1640723566.
3. Expected behavior: "zap" Registers the xdg-protocol properly under the .desktop and mimeapps.list files.