appdata: Use launchable rather than id

<id> should be used for the component id and <launchable> for the
desktop file.

demos/gtk-demo/org.gtk.Demo4.appdata.xml.in

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <component type="desktop">
-  <id>org.gtk.Demo4.desktop</id>
+  <id>org.gtk.Demo4</id>
+  <launchable type="desktop-id">org.gtk.Demo4.desktop</launchable>
   <metadata_license>CC0-1.0</metadata_license>
   <project_license>LGPL-2.1-or-later</project_license>
   <name>GTK Demo</name>

demos/icon-browser/org.gtk.IconBrowser4.appdata.xml.in

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <component type="desktop">
-  <id>org.gtk.IconBrowser4.desktop</id>
+  <id>org.gtk.IconBrowser4</id>
+  <launchable type="desktop-id">org.gtk.IconBrowser4.desktop</launchable>
   <metadata_license>CC0-1.0</metadata_license>
   <project_license>LGPL-2.1-or-later</project_license>
   <name>GTK Icon Browser</name>

demos/print-editor/org.gtk.PrintEditor4.appdata.xml

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <component type="desktop">
-  <id>org.gtk.PrintEditor4.desktop</id>
+  <id>org.gtk.PrintEditor4</id>
+  <launchable type="desktop-id">org.gtk.PrintEditor4.desktop</launchable>
   <metadata_license>CC0-1.0</metadata_license>
   <project_license>LGPL-2.1-or-later</project_license>
   <name>GTK Print Editor</name>

demos/widget-factory/org.gtk.WidgetFactory4.appdata.xml.in

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <component type="desktop">
-  <id>org.gtk.WidgetFactory4.desktop</id>
+  <id>org.gtk.WidgetFactory4</id>
+  <launchable type="desktop-id">org.gtk.WidgetFactory4.desktop</launchable>
   <metadata_license>CC0-1.0</metadata_license>
   <project_license>LGPL-2.1-or-later</project_license>
   <name>GTK Widget Factory</name>