twm: add page (#4377)

pages/common/twm.md

@@ -0,0 +1,24 @@
+# twm
+
+> A window manager for the X Window sytem.
+> More information: <https://gitlab.freedesktop.org/xorg/app/twm>.
+
+- Connect to the default X server:
+
+`twm`
+
+- Connect to a specific X server:
+
+`twm -display {{display}}`
+
+- Only manage the default screen:
+
+`twm -s`
+
+- Use a specific startup file:
+
+`twm -f {{path/to/file}}`
+
+- Enable verbose mode and print unexpected errors in X:
+
+`twm -v`