patch 9.1.1578: configure: comment still mentions autoconf 2.71

Problem:  configure: comment still mentions autoconf 2.71 to generate
          the configure script
Solution: Update the comment to use autoconf 2.72 instead (Yee Chin Cheng).

Vim v9.1.1369 updated the autoconf generation to be done using 2.72.
Update comments to reflect that.

closes: #17815

Signed-off-by: Yee Cheng Chin <ychin.git@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

Author: ychin

src/configure.ac

@@ -1,6 +1,6 @@
 dnl configure.ac: autoconf script for Vim
 
-dnl Process this file with autoconf 2.71 to produce "configure".
+dnl Process this file with autoconf 2.72 to produce "configure".
 
 AC_INIT
 AC_CONFIG_SRCDIR([vim.h])

src/version.c

@@ -719,6 +719,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1578,
 /**/
     1577,
 /**/