Update change_notes/2026-05-18-fix-fp-misra-c-13-4.md

Co-authored-by: Michael R Fairhurst <MichaelRFairhurst@github.com>

Author: mbaluda

change_notes/2026-05-18-fix-fp-misra-c-13-4.md

@@ -1,4 +1,5 @@
 - `RULE-13-4` - `ResultOfAnAssignmentOperatorShouldNotBeUsed`:
-  - Fixed false positives and false negatives.
+  - Fixed false positives for `=` assignments in for loop update expression.
+  - Fixed false negatives for when the result of compound assignment operators (`+=`, etc) are used.
 - `RULE-8-18-2` - `ResultOfAnAssignmentOperatorShouldNotBeUsed`:
   - Fixed false positives and false negatives.