See #6200 for a complete description of the issue. In short, we generate
inconsistent names for object types depending on whether or not they are
transitively reachable from resources or functions, which risks
unintentional breaking changes due to schema updates.
1. Name "input" types differently: `TArgs` for a type that is used in
resource inputs, having `Input<T>` properties, and `T` for a type
that is used in invoke inputs. The same schema type can produce both.
2. Always keep the name `T` for output types, avoid appending `Result` to
the name.
3. As needed, introduce a flag in the existing providers' schemas to avoid
breaking changes. Consider removing it on a major version bump.
Fixes#6200.