patch 9.1.0552: No test for antlr4 filetype

Problem:  No test for antlr4 filetype
          (after 9.1.0550)
Solution: Add a simple filename test

related: #15191

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/version.c b/src/version.c
index b745bd0..27cced4 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    552,
+/**/
     551,
 /**/
     550,