Replace namespaces with prefixes

Author: jariq

docs/reference/ID-Prefix-Reservation.md

@@ -60,7 +60,7 @@ When a package comes from a reserved prefix, you see the below visual indicators
 
 1. Review the acceptance [criteria for prefix ID reservation](#id-prefix-reservation-criteria).
 
-2. Determine the namespaces you want to reserve, in addition to any [advanced prefix reservation scenarios](#advanced-prefix-reservation-scenarios) you may require.
+2. Determine the prefixes you want to reserve, in addition to any [advanced prefix reservation scenarios](#advanced-prefix-reservation-scenarios) you may require.
 
 3. Send a mail to [[email protected]](mailto:[email protected]) with the owner display name on [nuget.org](https://www.nuget.org/), as well as any reserved prefixes you are requesting. If you are delegating prefix subsets to multiple owners, make sure you mention all owner display names and prefix subsets.