updating error doc

Author: jbedard

docs/content/error/$compile/badrestrict.ngdoc

@@ -5,8 +5,14 @@
 
 This error occurs when the restrict property of a directive is not valid.
 
-The directive restrict property must be a string with possible character values being:
+The directive restrict property must be a string including one of more of the following characters:
 * E (element)
 * A (attribute)
 * C (class)
-* M (comment)
+* M (comment)
+
+For example:
+```javascript
+restrict: 'E'
+restrict: 'EAC'
+```