remove chapter update warning

Author: Xronophobe

chapter_15_advanced_forms.asciidoc

@@ -1,16 +1,6 @@
 [[chapter_15_advanced_forms]]
 == More Advanced Forms
 
-.🚧 Warning, Chapter update in progress
-*******************************************************************************
-This chapter is currently in the process of being rewritten for the 3e.
-
-The code listings should all be valid,
-and work with Python3.12 + Django 4,
-but I haven't reviewed the chapter text in detail yet.
-
-*******************************************************************************
-
 // TODO Harry write a paragraph about the server side validation