Correct a type error (#3272)

tempate -> template

Author: byungjune

public/docs/ts/latest/guide/template-syntax.jade

@@ -161,7 +161,7 @@ h3#expression-context Expression context
   The context for terms in an expression is a blend of the _template variables_, 
   the directive's _context_ object (if it has one), and the component's _members_.
   If you reference a name that belongs to more than one of these namespaces,
-  the tempate variable name takes precedence, followed by a name in the directive's' _context_,
+  the template variable name takes precedence, followed by a name in the directive's' _context_,
   and, lastly, the component's member names.
 
   The previous example presents such a name collision. The component has a `hero` property and the `*ngFor` defines a `hero` template variable. The `hero` in `{{hero}}` refers to the template input variable, not the component's property.