changes.src: update 2.15.03 release notes

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
diff --git a/doc/changes.src b/doc/changes.src
index 42fc031..47fb03b 100644
--- a/doc/changes.src
+++ b/doc/changes.src
@@ -16,9 +16,14 @@
 \b Debug information now properly reflect the line numbers of macro
 invocations (unless declared \c{.nolist}).
 
-\b Fix alignment of sections in the \c{coff}/\c{win32}/\c{win64}
-output formats when the desired alignment is less than the default
-alignment for the section or section type.
+\b Fix excessive alignment of sections in the
+\c{coff}/\c{win32}/\c{win64} output formats when the user-specified
+alignment is less than the default alignment for the section or
+section type.
+
+\b Fix explicit token pasting (\c{%+}, \k{concat%+}) for the cases
+where one or more parts result from empty token expansion, resulting
+in \c{%+} tokens at the beginning or end, or multiple ones in a row.
 
 \b Portability fixes.