soulseekqt: fixed desktop file (#338405)

      # fixup and install desktop file

      desktop-file-install --dir $out/share/applications \

        --set-key Exec --set-value $binary \

        --set-key Exec --set-value SoulseekQt \

        --set-key Terminal --set-value false \

        --set-key Comment --set-value "${meta.description}" \

        --set-key Categories --set-value Network ${appextracted}/default.desktop

      mv $out/share/applications/default.desktop $out/share/applications/SoulseekQt.desktop