swayidle: add page (#11586)

pages/linux/swayidle.md

@@ -0,0 +1,13 @@
+# swayidle
+
+> Idle management daemon for Wayland.
+> Note: the configuration options are documented in its man page.
+> More information: <https://github.com/swaywm/swayidle/blob/master/swayidle.1.scd>.
+
+- Listen for idle activity using the configuration in `$XDG_CONFIG_HOME/swayidle/config` or `$HOME/swayidle/config`:
+
+`swayidle`
+
+- Specify an alternative path to the configuration file:
+
+`swayidle -C {{path/to/file}}`