Update runtime files.
diff --git a/runtime/doc/usr_41.txt b/runtime/doc/usr_41.txt
index dd0583b..07d11f8 100644
--- a/runtime/doc/usr_41.txt
+++ b/runtime/doc/usr_41.txt
@@ -1,4 +1,4 @@
-*usr_41.txt* For Vim version 8.1. Last change: 2019 Jan 12
+*usr_41.txt* For Vim version 8.1. Last change: 2019 Jan 29
VIM USER MANUAL - by Bram Moolenaar
@@ -771,7 +771,7 @@
systemlist() get the result of a shell command as a list
hostname() name of the system
readfile() read a file into a List of lines
- writefile() write a List of lines into a file
+ writefile() write a List of lines or Blob into a file
Date and Time: *date-functions* *time-functions*
getftime() get last modification time of a file
@@ -941,6 +941,7 @@
test_override() test with Vim internal overrides
test_garbagecollect_now() free memory right now
test_ignore_error() ignore a specific error message
+ test_null_blob() return a null Blob
test_null_channel() return a null Channel
test_null_dict() return a null Dict
test_null_job() return a null Job