patch 8.2.0843: filetype elm not detected

Problem:    Filetype elm not detected.
Solution:   Recognize *.elm files. (closes #6157)
diff --git a/src/version.c b/src/version.c
index 641b375..349ecbe 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    843,
+/**/
     842,
 /**/
     841,