patch 9.1.0980: no support for base64 en-/decoding functions in Vim Script

Problem:  no support for base64 en-/decoding functions in Vim Script
          (networkhermit)
Solution: Add the base64_encode() and base64_decode() functions
          (Yegappan Lakshmanan)

fixes: #16291
closes: #16330

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/usr_41.txt b/runtime/doc/usr_41.txt
index 36907d2..fdb9934 100644
--- a/runtime/doc/usr_41.txt
+++ b/runtime/doc/usr_41.txt
@@ -1,4 +1,4 @@
-*usr_41.txt*	For Vim version 9.1.  Last change: 2024 Nov 11
+*usr_41.txt*	For Vim version 9.1.  Last change: 2024 Dec 30
 
 		     VIM USER MANUAL - by Bram Moolenaar
 
@@ -1263,6 +1263,8 @@
 	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
+	base64_encode()		encode a blob into a base64 string
+	base64_decode()		decode a base64 string into a blob
 	err_teapot()		give error 418 or 503
 
 Jobs:						*job-functions*