Addendum readme.md what needs to be installed for correct operation

src/linux/README.md

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+### Only Debian is supported
+
+#### For the GNOME graphical shell
+
+### For the correct operation of the application and the app tray, you need
+1. Install `gnome-shell-extension-appindicator`
+```shell
+$ sudo apt install gnome-shell-extension-appindicator
+```
+2. Search `tweaks` in your `Activities` screen
+3. Switch `Kstatusnotifieritem/appindicator support` on
+
+### To work correctly on the KDE Plasma graphical shell, you need
+
+Install `gir1.2-appindicator3-0.1`
+
+```shell
+$ sudo apt install gir1.2-appindicator3-0.1
+```