add undocumented range feature of v-repeat

Author: cheeses2

source/api/directives.md

@@ -126,12 +126,12 @@ Will render:
 ### v-repeat
 
 - This directive creates child Vue instances.
-- This directive requires the value to be an Array or Object.
+- This directive requires the value to be an Array, Object or Number.
 - This directive can trigger transitions.
 - This directive accepts an optional argument.
 - Directive params: `trackby`
 
-Create a child ViewModel for every item in the binding Array. These child ViewModels will be automatically created / destroyed when mutating methods, e.g. `push()`, are called on the Array.
+Create a child ViewModel for every item in the binding Array or Object. If the value is a whole Number then that many child ViewModels are created. These child ViewModels will be automatically created / destroyed when mutating methods, e.g. `push()`, are called on the Array or Object, or the number is increased or decreased.
 
 When no argument is provided, the child ViewModel will directly use the assigned element in the Array as its `$data`. If the value is not an object, a wrapper data object will be created and the value will be set on that object using the alias key `$value`.