Update runtime files.
diff --git a/runtime/doc/diff.txt b/runtime/doc/diff.txt
index 2c1233b..40167a1 100644
--- a/runtime/doc/diff.txt
+++ b/runtime/doc/diff.txt
@@ -1,4 +1,4 @@
-*diff.txt* For Vim version 9.0. Last change: 2022 Dec 24
+*diff.txt* For Vim version 9.0. Last change: 2023 Jan 21
VIM REFERENCE MANUAL by Bram Moolenaar
@@ -136,7 +136,7 @@
buffers.
The `:diffoff` command resets the relevant options to the values they had when
-using `:diffsplit`, `:diffpatch` , `:diffthis`. or starting Vim in diff mode.
+using `:diffsplit`, `:diffpatch`, `:diffthis`. or starting Vim in diff mode.
When using `:diffoff` twice the last saved values are restored.
Otherwise they are set to their default value: