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/todo.txt b/runtime/doc/todo.txt
index 342332e..48937b1 100644
--- a/runtime/doc/todo.txt
+++ b/runtime/doc/todo.txt
@@ -1,4 +1,4 @@
-*todo.txt*      For Vim version 9.1.  Last change: 2024 Dec 16
+*todo.txt*      For Vim version 9.1.  Last change: 2024 Dec 30
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -4198,8 +4198,6 @@
 	char2hex()		convert char string to hex string.
 	crypt()			encrypt string
 	decrypt()		decrypt string
-	base64enc()		base 64 encoding
-	base64dec()		base 64 decoding
 	attributes()		return file protection flags "drwxrwxrwx"
 	shorten(fname)		shorten a file name, like home_replace()
 	perl(cmd)		call Perl and return string