changes.src: add obj2 output format to the release notes

Need to be added to the release notes...

Cc: KO Myung-Hun <komh78@gmail.com>
Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>

Author: H. Peter Anvin

doc/changes.src

@@ -12,7 +12,8 @@ It is the production version of NASM since 2025.
 
 \S{cl-3.00.01} Version 3.00.01
 
-Put the updates for NASM 3.00.01 here...
+\b A new \c{obj2} version of the \c{obj} output format, intended for
+   use on OS/2. See \k{obj2fmt}.
 
 \S{cl-3.00} Version 3.00