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/testdir/test_filetype.vim b/src/testdir/test_filetype.vim
index 379f6a1..202cab4 100644
--- a/src/testdir/test_filetype.vim
+++ b/src/testdir/test_filetype.vim
@@ -95,6 +95,7 @@
     aml: ['file.aml'],
     ampl: ['file.run'],
     ant: ['build.xml'],
+    antlr4: ['parser.g4'],
     apache: ['.htaccess', '/etc/httpd/file.conf', '/etc/apache2/sites-2/file.com', '/etc/apache2/some.config', '/etc/apache2/conf.file/conf', '/etc/apache2/mods-some/file', '/etc/apache2/sites-some/file', '/etc/httpd/conf.d/file.config', '/etc/apache2/conf.file/file', '/etc/apache2/file.conf', '/etc/apache2/file.conf-file', '/etc/apache2/mods-file/file', '/etc/apache2/sites-file/file', '/etc/apache2/sites-file/file.com', '/etc/httpd/conf.d/file.conf', '/etc/httpd/conf.d/file.conf-file', 'access.conf', 'access.conf-file', 'any/etc/apache2/conf.file/file', 'any/etc/apache2/file.conf', 'any/etc/apache2/file.conf-file', 'any/etc/apache2/mods-file/file', 'any/etc/apache2/sites-file/file', 'any/etc/apache2/sites-file/file.com', 'any/etc/httpd/conf.d/file.conf', 'any/etc/httpd/conf.d/file.conf-file', 'any/etc/httpd/file.conf', 'apache.conf', 'apache.conf-file', 'apache2.conf', 'apache2.conf-file', 'httpd.conf', 'httpd.conf-file', 'srm.conf', 'srm.conf-file', '/etc/httpd/mods-some/file', '/etc/httpd/sites-some/file', '/etc/httpd/conf.file/conf'],
     apachestyle: ['/etc/proftpd/file.config,/etc/proftpd/conf.file/file', '/etc/proftpd/conf.file/file', '/etc/proftpd/file.conf', '/etc/proftpd/file.conf-file', 'any/etc/proftpd/conf.file/file', 'any/etc/proftpd/file.conf', 'any/etc/proftpd/file.conf-file', 'proftpd.conf', 'proftpd.conf-file'],
     applescript: ['file.scpt'],
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,