idevice*, iproxy: add pages (#14363)

Co-authored-by: Juri Dispan <juri.dispan@posteo.net>
Co-authored-by: Wiktor Perskawiec <git@spageektti.cc>
Co-authored-by: Sebastiaan Speck <12570668+sebastiaanspeck@users.noreply.github.com>

pages/common/idevicescreenshot.md

@@ -0,0 +1,12 @@
+# idevicescreenshot
+
+> Get a screenshot from the connected iOS device.
+> More information: <https://manned.org/idevicescreenshot>.
+
+- Save a screenshot with the default file name as a TIFF image:
+
+`idevicescreenshot`
+
+- Save a screenshot with a specific file name:
+
+`idevicescreenshot {{path/to/file.tiff}}`