Property behaviors: typo

Author: jckarter

proposals/XXXX-property-behavior-decls.md

@@ -191,7 +191,8 @@ print(x) // Invokes the `lazy` getter, initializing the property
 x = 679 // Invokes the `lazy` setter
 ```
 
-Visible members of the behavior can also be accessed under `property.behavior`:
+Visible members of the behavior can also be accessed under
+`property.[behavior]`:
 
 ```swift
 x.[lazy].clear() // Invokes `lazy`'s `clear` method