patch 9.0.0084: using "terraform" filetype for .tfvars file is bad

Problem:    Using "terraform" filetype for .tfvars file is bad.
Solution:   use "terraform-vars", so that different completion and other
            mechanisms can be used. (Radek Simko, closes #10755)

runtime/filetype.vim

@@ -1982,8 +1982,8 @@ au BufRead,BufNewFile *.ttl
 " Terminfo
 au BufNewFile,BufRead *.ti			setf terminfo
 
-" Terraform
-au BufRead,BufNewFile *.tfvars			setf terraform
+" Terraform variables
+au BufRead,BufNewFile *.tfvars			setf terraform-vars
 
 " TeX
 au BufNewFile,BufRead *.latex,*.sty,*.dtx,*.ltx,*.bbl	setf tex

src/testdir/test_filetype.vim

@@ -549,7 +549,7 @@ let s:filename_checks = {
     \ 'template': ['file.tmpl'],
     \ 'teraterm': ['file.ttl'],
     \ 'terminfo': ['file.ti'],
-    \ 'terraform': ['file.tfvars'],
+    \ 'terraform-vars': ['file.tfvars'],
     \ 'tex': ['file.latex', 'file.sty', 'file.dtx', 'file.ltx', 'file.bbl'],
     \ 'texinfo': ['file.texinfo', 'file.texi', 'file.txi'],
     \ 'texmf': ['texmf.cnf'],

src/version.c

@@ -735,6 +735,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    84,
 /**/
     83,
 /**/