Tweaks to release notes.

docs/topics/2.2-release-notes.md

@@ -77,6 +77,10 @@ The implicit to-many behavior on serializers, and the `ManyRelatedField` style c
 
 Serializer relationships for nullable Foreign Keys will change from using the current `null=True` flag, to instead using `required=False`.
 
+For example, is a user account has an optional foreign key to a company, that you want to express using a hyperlink, you might use the following field in a `Serializer` class:
+
+    current_company = serializers.HyperlinkedRelatedField(required=False)
+
 This is in line both with the rest of the serializer fields API, and with Django's `Form` and `ModelForm` API.
 
 Using `required` throughout the serializers API means you won't need to consider if a particular field should take `blank` or `null` arguments instead of `required`, and also means there will be more consistent behavior for how fields are treated when they are not present in the incoming data. 
@@ -87,7 +91,9 @@ The `null=True` argument will continue to function, and will imply `required=Fal
 
 The `CharField` API previously took an optional `blank=True` argument, which was intended to differentiate between null CharField input, and blank CharField input.
 
-In keeping with Django's CharField API, REST framework's `CharField` will only ever return the empty string, for missing or `None` inputs.  The `blank` flag will no longer be in use, and you should instead just use the `required=<bool>` flag.
+In keeping with Django's CharField API, REST framework's `CharField` will only ever return the empty string, for missing or `None` inputs.  The `blank` flag will no longer be in use, and you should instead just use the `required=<bool>` flag.  For example:
+
+    extra_details = CharField(required=False)
 
 The `blank` keyword argument will continue to function, but will raise a `PendingDeprecationWarning`.