NEWS entry for deletion of length(::Stateful)

Will update History.md on master if this gets merged.

xref JuliaLang#47790

xref JuliaLang#51747

xref JuliaLang#54953

NEWS.md

@@ -134,6 +134,10 @@ Standard library changes
   writes 4 bytes for each character, instead of writing the UTF-8 representation of each character.
   The new format is compatible with that used by `Array`, making it possible to use `read!` to get
   the data back ([#42593]).
+* It's not possible to define `length` for stateful iterators in a generally consistent manner. The
+  potential for silently incorrect results for `Stateful` iterators is addressed by deleting the
+  `length(::Stateful)` method. The last type parameter of `Stateful` is gone, too. Issue: ([#47790]),
+  PR: ([#51747]).
 
 #### StyledStrings
 
@@ -218,6 +222,9 @@ Tooling Improvements
   failing typo CI check, then the reported typos will be automatically ignored in future CI
   runs on PRs that edit those same files ([#51704]).
 
+[#47790]: https://github.com/JuliaLang/julia/issues/47790
+[#51747]: https://github.com/JuliaLang/julia/issues/51747
+
 <!--- generated by NEWS-update.jl: -->
 [#28705]: https://github.com/JuliaLang/julia/issues/28705
 [#33892]: https://github.com/JuliaLang/julia/issues/33892