patch 9.1.0593: filetype: Asymptote files are not recognized

Problem:  filetype: Asymptote files are not recognized
Solution: detect '*.asy' files as asy filetype, include
          ftplugin and syntax plugin (AvidSeeker).

Reference: https://asymptote.sourceforge.io/

closes: #15252

Signed-off-by: AvidSeeker <avidseeker7@protonmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/version.c b/src/version.c
index c6b6248..49aeb92 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    593,
+/**/
     592,
 /**/
     591,