patch 8.1.1284: detecting *.tmpl as htmlcheetah is outdated

Problem:    Detecting *.tmpl as htmlcheetah is outdated.
Solution:   Use the generic name "template". (closes #4348)
diff --git a/src/version.c b/src/version.c
index 892d1a5..bb310e2 100644
--- a/src/version.c
+++ b/src/version.c
@@ -768,6 +768,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1284,
+/**/
     1283,
 /**/
     1282,