Use full path in undofile().  Updated docs.
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index 498df7f..63efd1c 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -7265,10 +7265,11 @@
 		set ul=0
 <	But you can also get Vi compatibility by including the 'u' flag in
 	'cpoptions', and still be able to use CTRL-R to repeat undo.
+	Also see |undo-two-ways|.
 	Set to a negative number for no undo at all: >
 		set ul=-1
 <	This helps when you run out of memory for a single change.
-	Also see |undo-two-ways|.
+	Also see |clear-undo|.
 
 						*'updatecount'* *'uc'*
 'updatecount' 'uc'	number	(default: 200)