fixed a syntax error in vim.snippets.

Author: SirVer

snippets/vim.snippets

@@ -25,9 +25,8 @@ snippet for
 snippet forkv
 	for [${1},${2}] in items(${3})
 		${0}
-            unlet $1 $2
+		unlet $1 $2
 	endfor
-
 snippet wh
 	while ${1}
 		${0}