fix: reorder some paragraphs

Author: Ddystopia

text/0000-forget-marker-trait.md

@@ -14,13 +14,11 @@ Add a `Forget` marker trait indicating whether it is safe to skip the destructor
 # Motivation
 [motivation]: #motivation
 
-Many Rust programmers may find the biggest problem with `Forget` to be migration. But this RFC describes how migration can be done easily. See [#migration](#migration) section for details.
+Back in 2015, the [decision was made][safe-mem-forget] to make `mem::forget` safe, making every type effectively implement `Forget`. All the APIs in `std` were able remain safe after this change, except one. This RFC is not targeted at resource leaks in general, but is instead focused on allowing a number of APIs to become safe, by providing new unsafe guarantees using `Forget`.
 
 In short, the lack of `!Forget` types undermines lifetimes, sacrificing all 3 of performance, ergonomics and efficiency. Most Rust code, as well as external APIs, naturally converge towards `!Forget` types, but in the absence of `Forget` trait support, those APIs use a mixture of `Arc`, `'static`, allocations, etc.
 
----
-
-Back in 2015, the [decision was made][safe-mem-forget] to make `mem::forget` safe, making every type effectively implement `Forget`. All the APIs in `std` were able remain safe after this change, except one. This RFC is not targeted at resource leaks in general, but is instead focused on allowing a number of APIs to become safe, by providing new unsafe guarantees using `Forget`.
+Many Rust programmers may find the biggest problem with `Forget` to be migration. But this RFC describes how migration can be done easily. See [#migration](#migration) section for details.
 
 [safe-mem-forget]: https://github.com/rust-lang/rfcs/pull/1066