runtime(doc): document vim-script library function

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/pi_zip.txt b/runtime/doc/pi_zip.txt
index 8673324..14ae340 100644
--- a/runtime/doc/pi_zip.txt
+++ b/runtime/doc/pi_zip.txt
@@ -1,4 +1,4 @@
-*pi_zip.txt*	For Vim version 9.0.  Last change: 2023 Mar 12
+*pi_zip.txt*	For Vim version 9.0.  Last change: 2023 Nov 05
 
 				+====================+
 				| Zip File Interface |
@@ -70,6 +70,13 @@
    extract a file from a zip archive.  By default, >
 	let g:zip_extractcmd= g:zip_unzipcmd
 <
+							*g:zip_exec*
+   For security reasons, one may prevent that Vim runs executables
+   automatically when opening a buffer.  This option (default: "1")
+   can be used to prevent executing the "unzip" command when set to
+   "0": >
+	let g:zip_exec=0
+<
    PREVENTING LOADING~
 
    If for some reason you do not wish to use vim to examine zipped files,