New lint: Unnecessarily complex types

It would be nice to lint on return types that are more complex than necessary. Take for example the following function (playground):

fn unnecessary_result() -> Result<usize, ()> {
    Ok(1)
}

The Result here is not necessary, because the function always returns an Ok variant.
I would also like to see a similar lint for fn f() -> Option<T> where f always returns Some.

Note this is not the same as https://rust-lang.github.io/rust-clippy/current/index.html#type_complexity, which is about return types that are hard to read, not return types that are unnecessary.

Possible output for the lint (just making this up here):

warning: unnecessary `Result` in return type
 --> src/lib.rs:1:1
   |
1  |  fn unnecessary_result() -> Result<usize, ()> {
   |                             ^^^^^^^^^^^^^^^^^ help: try removing the `Result` type: `usize`
2  |         Ok(1)
   |         ^^^^^ note: only return value is an `Ok` variant

Start by comparing the proposed lint with Clippy's existing type_complexity lint and the issue's Result and Option examples. Done means detecting functions whose returns are always Ok or Some and producing a diagnostic that explains the unnecessary wrapper and suggested simpler type.