Avoid suggesting not upgrading; let compat notes stand on their own

Author: joshtriplett

posts/2022-09-22-Rust-1.64.0.md

@@ -245,8 +245,6 @@ These APIs are now usable in const contexts:
 
 ### Compatibility notes
 
-Rust 1.64 includes some changes that might prevent you from upgrading:
-
 * As [previously
   announced](https://blog.rust-lang.org/2022/08/01/Increasing-glibc-kernel-requirements.html),
   `linux` targets now require at least Linux kernel 3.2 (except for targets which