Nested generic parameters must be manually inlined

[JMLX42]

Problem

Follow up on #1182 / #1184

The new behavior for generic types is as follow:

• If it's a native type, force inline = true except if #[schema(inline = false)] is specified (because if it is specified, maybe someone does actually want to make their own u32 schema?).
• If #[schema(inline = ...)] is specified, use it.
• Otherwise, assume #[schema(inline = true)] (in order to keep the existing behavior).

But an edge case remains (cf this comment).

Nested generics need to be inlined manually in some cases.

Here is an example:

   #[derive(ToSchema)]
   #[schema(as = path::MyType<T>)]
   struct Type<T> {
       t: T,
   }

   #[derive(ToSchema)]
   struct Person<T: Sized, P> {
       field: T,
       t: P,
   }

In this case:

1. Person<String, Type<MyStruct> will work as expected.
2. Person<String, Type<i32> will not work, because it will generate an invalid reference to the the i32 schema ("$ref": "#/components/schemas/i32") instead of inlining the i32 schema.

Workaround

To workaround case 2., #[schema(inline)] must be added manually on the nested generic's field(s):

   #[derive(ToSchema)]
   #[schema(as = path::MyType<T>)]
   struct Type<T> {
       #[schema(inline)]
       t: T,
   }

   #[derive(ToSchema)]
   struct Person<T: Sized, P> {
       field: T,
       #[schema(inline)]
       t: P,
   }

To Do

• Find an actual fix