Improve record size limit changelog wording

Signed-off-by: Waleed Elmelegy <waleed.elmelegy@arm.com>
diff --git a/ChangeLog.d/add-record-size-limit-extension-support.txt b/ChangeLog.d/add-record-size-limit-extension-support.txt
index ca1a7c2..bc95400 100644
--- a/ChangeLog.d/add-record-size-limit-extension-support.txt
+++ b/ChangeLog.d/add-record-size-limit-extension-support.txt
@@ -1,2 +1,5 @@
 Features
-   * Add support for sending and receiving Record Size Limit extension.
+   * Add support for Record Size Limit extension as defined by RFC 8449
+     and configured with MBEDTLS_SSL_RECORD_SIZE_LIMIT.
+     Application data sent and received will be fragmented according to
+     Record size limits negotiated during handshake.