docs($q): note that function okToGreet is expected to be defined in example
docs($q): note that function okToGreet is expected to be defined in example

the function okToGreet wasn't defined, so this example wouldn't work properly.

I've decided that instead of adding unrelated code to the example, it should just be noted that the
function is expected to be defined in the lexical scope.

Closes #5878

ammula88/angular.js,ammula88/angular.js,ammula88/angular.js,ammula88/angular.js,ammula88/angular.js