/doc/autoupdate.rst: "Migrate to the following directory" => "Edit this Registry key"

Registry keys are no directories; you would not "migrate" to keys if you are just about to switch to them; resembling formulas as "Edit these / this Registry key/s" ease fast reading, for that also ":" instead of "::" at the end (formatting what follows)

doc/autoupdate.rst

@@ -87,7 +87,7 @@ To prevent automatic updates and disallow manual overrides:
 .. note::This is the preferred method of controlling the updater behavior using 
    Group Policies.
 
-1. Migrate to the following directory::
+1. Edit this Registry key:
 
 	HKEY_LOCAL_MACHINE\Software\Policies\ownCloud\ownCloud