Switch tray to symbolic icons

This allows to rely on GTK recoloring rather than requiring the user to have an icon theme

Telegram/SourceFiles/platform/linux/specific_linux.cpp

@@ -494,6 +494,25 @@ void InstallLauncher() {
 		DEBUG_LOG(("App Info: Icon copied to '%1'").arg(icon));
 	}
 
+	const auto symbolicIcons = icons + u"/hicolor/symbolic/apps/"_q;
+	if (!QDir().exists(symbolicIcons)) QDir().mkpath(symbolicIcons);
+
+	const auto monochromeIcons = {
+		QString(),
+		u"attention"_q,
+		u"mute"_q,
+	};
+
+	for (const auto &icon : monochromeIcons) {
+		QFile::copy(
+			u":/gui/icons/tray/monochrome%1.svg"_q.arg(
+				!icon.isEmpty() ? u"_"_q + icon : QString()),
+			symbolicIcons
+				+ ApplicationIconName()
+				+ (!icon.isEmpty() ? u"-"_q + icon : QString())
+				+ u"-symbolic.svg"_q);
+	}
+
 	QProcess::execute("update-desktop-database", {
 		applicationsPath
 	});