add news entry for #45276 and #45404

NEWS.md

@@ -25,6 +25,10 @@ Language changes
 Compiler/Runtime improvements
 -----------------------------
 
+* The known quadratic behavior of type inference is now fixed and inference uses less memory in general.
+  Certain edge cases with auto-generated long functions (e.g. ModelingToolkit.jl with partial
+  differential equations and large causal models) should see significant compile-time improvements.
+  ([#45276], [#45404])
 
 Command-line option changes
 ---------------------------