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/idevicediagnostics.md

@@ -0,0 +1,16 @@
+# idevicediagnostics
+
+> Interact with the diagnostics interface of an iOS device.
+> More information: <https://manned.org/idevicediagnostics>.
+
+- Print diagnostics information:
+
+`idevicediagnostics diagnostics`
+
+- Print mobilegestalt key values:
+
+`idevicediagnostics mobilegestalt {{key1}} {{key2}}`
+
+- Shutdown, restart or sleep the device:
+
+`idevicediagnostics {{shutdown|restart|sleep}}`