fix filter syntax (close #78)

Author: yyx990803

source/api/filters.md

@@ -32,14 +32,14 @@ Pluralizes the argument based on the filtered value. When there is exactly one a
 **Example:**
 
 ``` html
-{{count}} {{count | pluralize item}}
+{{count}} {{count | pluralize 'item'}}
 ```
 
 *1 => '1 item'*  
 *2 => '2 items'*
 
 ``` html
-{{date}}{{date | pluralize st nd rd th}}
+{{date}}{{date | pluralize 'st' 'nd' 'rd' 'th'}}
 ```
 
 Will result in:
@@ -79,7 +79,7 @@ Wrap the handler so it only gets called when the keyCode matches the argument. Y
 **Example:**
 
 ``` html
-<input v-on="keyup:doSomething | key enter">
+<input v-on="keyup:doSomething | key 'enter'">
 ```
 
 `doSomething` will only be called when the Enter key is pressed.

source/guide/events.md

@@ -85,7 +85,7 @@ It also has a few presets for commonly used keys:
 
 ```
 <!-- same as above -->
-<input v-on="keyup:submit | key enter">
+<input v-on="keyup:submit | key 'enter'">
 ```
 
 Check the API reference for a [full list of key filter presets](/api/filters.html#key).
@@ -98,4 +98,4 @@ You might be concerned that this whole event listening approach violates the goo
 2. Since you don't have to manually attach event listeners in JS, your ViewModel code can be pure logic and DOM-free. This makes it easier to test.
 3. When a ViewModel is destroyed, all event listeners are automatically removed. You don't need to worry about cleaning it up yourself.
 
-Next up: [Handling Forms](/guide/forms.html).
+Next up: [Handling Forms](/guide/forms.html).