docs: updated doc for field and entity caching

[tusharmath]

Updating documentation for caching

[tusharmath]

We can drop this doc.

[tusharmath]

Suggested change

	Field level caching enables caching for any field or query
	which contains a resolver.
	Field level caching enables caching for any field which contains a resolver.

[tusharmath]

Suggested change

	user_id: Int @cache(maxAge: 100)
	userId: Int @cache(maxAge: 100)

[tusharmath]

Suggested change

	user: User @http(path: "/user/{{user_id}}") @cache(maxAge: 200)
	user: User @http(path: "/user/{{value.userId}}") @cache(maxAge: 200)

[tusharmath]

Suggested change

	For the above config, the result of `user` field will be cached because it contains an http resolver. However, the output of `user_id` will not be cached because it doesn't have a resolver for itself, it's value is fetched by the resolver at the `posts` query.
	For the above config, the result of `user` field will be cached because it contains an http resolver. However, the output of `userId` & `title` will not be cached because it doesn't have a resolver for itself, it's value is fetched by the resolver at the `posts` field having the `@http(path: "/posts")` directive.

[tusharmath]

Suggested change

	When the `cache` directive is applied to a type then it is inherited by each of the field of the type. Hence, the above config is equivalent to:
	When the `cache` directive is applied to a type then it is inherited by each of the field of the type. Hence, the above config can be reduced into:

[tusharmath]

Suggested change

	user: User @http(path: "/user/{{user_id}}") @cache(maxAge: 100)
	user: User @http(path: "/user/{{value.userId}}") @cache(maxAge: 100)

[tusharmath]

Suggested change

	user: User @http(path: "/user/{{user_id}}") @cache(maxAge: 100)
	user: User @http(path: "/user/{{value.userId}}") @cache(maxAge: 100)

[tusharmath]

Suggested change

	### Field level caching implementation
	### Implementing Cache Key

[tusharmath]

Suggested change

	user: User @http(path: "/user/{{user_id}}") @cache(maxAge: 100)
	user: User @http(path: "/user/{{value.id}}") @cache(maxAge: 100)

[tusharmath]

This implementation needs to change:

• cache directive to read the resolver applied and use only the arguments on the resolver as key. It should not matter where the resolver is called from, for each query.

For eg: in @http(path: "/users/{{value.id}}") we should have /users/{{value.id}} as the key. So for a request made to /users/1 irrespective of where the resolver is attached, we should read from the same cache. For eg: query {todos {user {name}}} and query {comments {user {name}}} and query {posts {user {name}}} should all share the same cache if to resolve user we hit /users API.