introduction.md: replace hard-to-read example

Author: tshepang

src/introduction.md

@@ -70,8 +70,8 @@ These conventions are documented here.
 
 * The main text describes the latest stable edition. Differences to previous editions are separated in edition blocks:
 
-  > [!EDITION-2018]
-  > In the 2015 edition, this syntax is valid that is disallowed as of the 2018 edition.
+  > [!EDITION-2024]
+  > This is an edition-specific difference.
 
 * Notes that contain useful information about the state of the book or point out useful, but mostly out of scope, information are in note blocks.