Added blurb to CHANGES & RELEASE

Signed-off-by: fazledyn-or <[email protected]>

Author: nydelzaf

CHANGES.txt

@@ -15,6 +15,10 @@ RELEASE  VERSION/DATE TO BE FILLED IN LATER
     - Fix of the --debug=sconscript option to return exist statements when using return
       statement with stop flag enabled
 
+  From Ataf Fazledin Ahamed:
+    - Use of NotImplemented instead of NotImplementedError for special methods
+      of _ListVariable class
+
 RELEASE 4.6.0 -  Sun, 19 Nov 2023 17:22:20 -0700
 
   From Max Bachmann:

RELEASE.txt

@@ -38,9 +38,8 @@ FIXES
 IMPROVEMENTS
 ------------
 
-- List improvements that wouldn't be visible to the user in the
-  documentation:  performance improvements (describe the circumstances
-  under which they would be observed), or major code cleanups
+- Use of NotImplemented instead of NotImplementedError for special methods
+  of _ListVariable class
 
 PACKAGING
 ---------