Improve generator type inferencing

[nickhendo]

Certain fields can have more information inferred from them, such as if a field is part of a for loop, we can reasonably infer that it is of type Iterable for example.

Another example would be within a field that is iterated through, we don't currently generate types for the fields that would be attached to that field. E.g.

            {% block post_grid %}
            {% for post in posts %}
            <div hx-get="{{ post.slug }}" class="bg-gradient-to-br from-gray-800/50 to-gray-900/50 rounded-2xl p-6 border border-gray-700/50 card-hover">
                <div class="flex items-center space-x-2 mb-4">
                    <span class="bg-volt-yellow/10 text-volt-yellow text-xs font-semibold px-3 py-1 rounded-full">{{ post.category }}</span>
                </div>
                <h3 class="text-xl font-bold mb-3 hover:text-volt-yellow transition-colors cursor-pointer">
                    {{ post.title }}
                </h3>
                <p class="text-gray-300 mb-4">
                    {{ post.description }}
                </p>
                <div class="flex items-center justify-between text-sm text-gray-400">
                    <span>{{ post.date }}</span>
                    <span>{{ post.read_time }}</span>
                </div>
            </div>
            {% endfor %}
            {% endblock %}

This generates the type posts (which should be inferred as an Iterable), but none of slug, title, description, date or read_time are generated.