docs: Update autoupdater.rst

fix typo and express sentence regarding update priority clearer

docs/features/autoupdater.rst

@@ -15,8 +15,8 @@ ecdsautils) can by found in the `contrib` directory. When creating the manifest,
 be set on the command line, or it can be taken from the ``site.mk``.
 
 The priority defines the maximum number of days that may pass between releasing an update and installation
-of the images. The update probability with start at 0 after the release time mentioned in the manifest
-and then slowly rise to 1 after the number of days given by the priority has passed.
+of the images. The update probability will start at 0 after the release time mentioned in the manifest
+and then slowly rise to 1 up to the point when the number of days given by the priority has passed.
 
 The priority may be an integer or a decimal fraction.
 
@@ -59,7 +59,7 @@ The server must be available via IPv6.
 Command Line
 ------------
 
-These commands can be used on a node.
+These commands can be used on a node:
 
 ::