patch 9.1.0591: filetype: *.wl files are not recognized

Problem:  filetype: *.wl files are not recognized
Solution: Detect '*.wl' files as Mathematica package files
          (Jonas Dujava)

closes: #15269

Signed-off-by: Jonas Dujava <jonas.dujava@gmail.com>
Signed-off-by: Doug Kearns <dougkearns@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/version.c b/src/version.c
index ae351cf..b9d85a6 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    591,
+/**/
     590,
 /**/
     589,