dunstctl: add page (#7547)

pages/linux/dunstctl.md

@@ -0,0 +1,20 @@
+# dunstctl
+
+> Control command for `dunst`.
+> More information: <https://manned.org/dunstctl>.
+
+- Pause notifications:
+
+`dunstctl set-paused true`
+
+- Un-pause notifications:
+
+`dunstctl set-paused false`
+
+- Close all notifications:
+
+`dunstctl close-all`
+
+- Display help:
+
+`dunstctl --help`