runtime(doc): update and remove  some invalid links

closes: #14748

Co-authored-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/pi_tar.txt b/runtime/doc/pi_tar.txt
index 0ab111c..5b317d6 100644
--- a/runtime/doc/pi_tar.txt
+++ b/runtime/doc/pi_tar.txt
@@ -1,4 +1,4 @@
-*pi_tar.txt*	For Vim version 9.1.  Last change: 2022 Oct 17
+*pi_tar.txt*	For Vim version 9.1.  Last change: 2024 May 11
 
 		       +====================+
 		       | Tar File Interface |
@@ -164,7 +164,8 @@
 	v2			* converted to use Vim7's new autoload feature
 				  by Bram Moolenaar
 	v1	(original)	* Michael Toren
-				  (see http://michael.toren.net/code/)
+				  (see http://michael.toren.net/code/
+				   link seems dead)
 
 ==============================================================================
 vim:tw=78:ts=8:noet:ft=help