Add warning to CHANGES and RELEASE

Author: Raymo111

CHANGES.txt

@@ -13,7 +13,9 @@ RELEASE  VERSION/DATE TO BE FILLED IN LATER
     - Fix issue #3935: OSErrors are now no longer hidden during execution of
       Actions. All exceptions during the execution of an Action are now
       returned by value rather than by raising an exception, for more
-      consistent behavior.
+      consistent behavior. With this change, user created Actions should now
+      catch and handle expected exceptions (whereas previously many of these
+      were silently caught and suppressed by the SCons Action exection code).
 
   From Mats Wichmann:
     - Updated Value Node docs and tests.

RELEASE.txt

@@ -32,7 +32,10 @@ CHANGED/ENHANCED EXISTING FUNCTIONALITY
 - Python 3.13 changes the behavior of isabs() on Windows. Adjust SCons
   usage of this in NodeInfo classes to avoid test problems.
 - All exceptions during the execution of an Action are now returned by value
-  rather than by raising an exception, for more consistent behavior.
+  rather than by raising an exception, for more consistent behavior. With this
+  change, user created Actions should now catch and handle expected exceptions
+  (whereas previously many of these were silently caught and suppressed by the
+  SCons Action exection code).
 
 FIXES
 -----