Add a changelog entry for the ann2rr change.

Author: tompollard

docs/changes.rst

@@ -77,6 +77,9 @@ Unreleased
 **Read and write .wfdb archive files**
   A record can be stored in a single ``.wfdb`` archive file (a ZIP file containing the header and signal files). ``rdrecord``, ``rdsamp``, ``rdheader`` and ``rdann`` read a record or its annotations from an archive when given the path of the archive, and ``wrsamp`` writes a record into an archive with the new ``wfdb_archive`` argument.
 
+**Use only beat annotations in ann2rr**
+  ``ann2rr`` now computes intervals between beat (QRS) annotations only, as the WFDB ``ann2rr`` program does, so rhythm changes, comments and other non-beat annotations no longer split an RR interval in two. The first interval is still measured from the start of the record. To include all annotations as before, pass ``all_annotations=True`` (the equivalent of ``ann2rr -A``).
+
 Version 4.3.1 (Feb 2026)
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