NEWS: Adapt YJIT support status to include OpenBSD

We don't run YJIT CI checks on OpenBSD so can't claim that we provide
first-class maintenance support. However, as of
3b2b28d035, YJIT can at least boot on OpenBSD.

NEWS.md

@@ -467,7 +467,7 @@ See [this blog post](https://shopify.engineering/yjit-just-in-time-compiler-crub
 
 * Fast warm-up times.
 
-* Limited to macOS & Linux on x86-64 platforms for now.
+* Limited to Unix-like x86-64 platforms for now.
 
 ## Static analysis