Give visual feedback while starting (spesmilo#4997)

See https://specifications.freedesktop.org/desktop-entry-spec/desktop-entry-spec-latest.html

Author: sajolida

electrum.desktop

@@ -10,7 +10,8 @@ Icon=electrum
 Name[en_US]=Electrum Bitcoin Wallet
 Name=Electrum Bitcoin Wallet
 Categories=Finance;Network;
-StartupNotify=false
+StartupNotify=true
+StartupWMClass=electrum
 Terminal=false
 Type=Application
 MimeType=x-scheme-handler/bitcoin;