11194: fix(gen-doc-assist): remove lifetimes in description of `new` r=Veykril a=numero-744
From wrong behavior:
```rust
/// Creates a new [`MyGenericStruct<'a, T>`].
```
to correct behavior:
```rust
/// Creates a new [`MyGenericStruct<T>`].
```
But I feel like there is a better way to implement it. Do you know if there is an existing function that could do the work of `lifetimes_removed()` below?
Co-authored-by: Côme ALLART <come.allart@etu.emse.fr>