changelog: use better wording and modify changelog section

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/ChangeLog.d/8482.txt b/ChangeLog.d/8482.txt
index 623d2e3..a392232 100644
--- a/ChangeLog.d/8482.txt
+++ b/ChangeLog.d/8482.txt
@@ -1,6 +1,6 @@
-Default behavior changes
+Changes
     * PSA_WANT_ALG_CCM and PSA_WANT_ALG_CCM_STAR_NO_TAG are no more synonyms and
       they are now treated separately. This means that they should be
-      individually enabled in order to enable relative support; also the
+      individually enabled in order to enable respective support; also the
       corresponding MBEDTLS_PSA_ACCEL symbol should be defined in case
       acceleration is required.