patch 9.1.0557: moving in the buffer list doesn't work as documented

Problem:  moving in the buffer list doesn't work as documented
          (SenileFelineS)
Solution: Skip non-help buffers, when run from normal buffers, else
          only move from help buffers to the next help buffer (LemonBoy)

As explained in the help section for :bnext and :bprev the commands
should jump from help buffers to help buffers (and from regular ones to
regular ones).

fixes: #4478
closes: #15198

Signed-off-by: LemonBoy <thatlemon@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/version9.txt b/runtime/doc/version9.txt
index df56215..ed1cd43 100644
--- a/runtime/doc/version9.txt
+++ b/runtime/doc/version9.txt
@@ -1,4 +1,4 @@
-*version9.txt*  For Vim version 9.1.  Last change: 2024 Jul 09
+*version9.txt*  For Vim version 9.1.  Last change: 2024 Jul 10
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -41580,6 +41580,9 @@
 - provide information about function arguments using the get(func, "arity")
   function |get()-func|
 - |:bwipe| also wipes jumplist and tagstack data
+- moving in the buffer list using |:bnext| and similar commands, behaves as
+  documented and skips help buffers (if not run from a help buffer, else 
+  moves to the next/previous help buffer).
 
 							*added-9.2*
 Added ~