changelog: add entry.

kivikakk · kivikakk · commit 0f030ac8ef0d · 2025-09-26T14:27:16.000+10:00
diff --git a/changelog.txt b/changelog.txt
@@ -1,3 +1,10 @@
+# [v0.43.0] - unreleased
+
+* `html::format_document`, `xml::format_document`, `cm::format_document` and
+  friends now take an `std::fmt::Write` as their `output` argument, instead of
+  an `std::io::Write`.
+
+
 # [v0.42.0] - 2025-09-24
 
 New APIs:
