Use headlinese for added functions, per request

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/ChangeLog.d/add_final_delay_accessor b/ChangeLog.d/add_final_delay_accessor
index 5e7844d..4b8117f 100644
--- a/ChangeLog.d/add_final_delay_accessor
+++ b/ChangeLog.d/add_final_delay_accessor
@@ -1,4 +1,4 @@
 Features
-   * Add the function mbedtls_timing_get_final_delay() to access the private
+   * Add function mbedtls_timing_get_final_delay() to access the private
      final delay field in an mbedtls_timing_delay_context, as requested in
      #5183.