patch 8.1.1284: detecting *.tmpl as htmlcheetah is outdated

Problem:    Detecting *.tmpl as htmlcheetah is outdated.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)

runtime/filetype.vim

@@ -713,8 +713,8 @@ au BufNewFile,BufRead *.erb,*.rhtml		setf eruby
 " HTML with M4
 au BufNewFile,BufRead *.html.m4			setf htmlm4
 
-" HTML Cheetah template
-au BufNewFile,BufRead *.tmpl			setf htmlcheetah
+" Some template.  Used to be HTML Cheetah.
+au BufNewFile,BufRead *.tmpl			setf template
 
 " Host config
 au BufNewFile,BufRead */etc/host.conf		setf hostconf

src/testdir/test_filetype.vim

@@ -200,7 +200,7 @@ let s:filename_checks = {
     \ 'hog': ['file.hog', 'snort.conf', 'vision.conf'],
     \ 'hostconf': ['/etc/host.conf'],
     \ 'hostsaccess': ['/etc/hosts.allow', '/etc/hosts.deny'],
-    \ 'htmlcheetah': ['file.tmpl'],
+    \ 'template': ['file.tmpl'],
     \ 'htmlm4': ['file.html.m4'],
     \ 'httest': ['file.htt', 'file.htb'],
     \ 'ibasic': ['file.iba', 'file.ibi'],

src/version.c

@@ -767,6 +767,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1284,
 /**/
     1283,
 /**/