patch 9.1.1321: filetype: MS ixx and mpp files are not recognized

Problem:  filetype: MS ixx and mpp files are not recognized
Solution: detect *.mpp and *.ixx files as c++ filetype
          (Hampus Avekvist)

closes: #17155

Signed-off-by: Hampus Avekvist <hampus.avekvist@hey.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/version.c b/src/version.c
index c255361..4c9f4ce 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1321,
+/**/
     1320,
 /**/
     1319,