blight: add page (#8633)

* blight: add page

* blight: adjust to change requests

* blight: fix arguments and fix command desc

pages/linux/blight.md

@@ -0,0 +1,24 @@
+# blight
+
+> Utility for changing the display brightness.
+> More information: <https://github.com/gutjuri/blight>.
+
+- Set display brightness to 50%:
+
+`blight set {{50}} -r`
+
+- Show current display brightness:
+
+`blight show`
+
+- Print maximum display brightness:
+
+`blight max`
+
+- Increase display brightness in %:
+
+`blight inc {{number}} -r`
+
+- Decrease display brightness with internal units:
+
+`blight dec {{number}}`