docs(rootScope): fix typo

Closes #5633

Author: kennethlynne

src/ng/rootScope.js

@@ -287,7 +287,7 @@ function $RootScopeProvider(){
            // No digest has been run so the counter will be zero
            expect(scope.foodCounter).toEqual(0);
 
-           // Run the digest but since food has not changed cout will still be zero
+           // Run the digest but since food has not changed count will still be zero
            scope.$digest();
            expect(scope.foodCounter).toEqual(0);