patch 9.0.1674: help for builtin functions is not sorted properly

Problem:    Help for builtin functions is not sorted properly.
Solution:   Put err_teapot() help in the right position.
diff --git a/runtime/doc/usr_41.txt b/runtime/doc/usr_41.txt
index 2d89e46..2d6792a 100644
--- a/runtime/doc/usr_41.txt
+++ b/runtime/doc/usr_41.txt
@@ -1232,6 +1232,7 @@
 	json_decode()		decode a JSON string to Vim types
 	js_encode()		encode an expression to a JSON string
 	js_decode()		decode a JSON string to Vim types
+	err_teapot()		give error 418 or 503
 
 Jobs:						*job-functions*
 	job_start()		start a job