Update truthy-and-falsy.md

Fixed nil value and small grammar fix.

docs/source/tutorials/truthy-and-falsy.md

@@ -6,7 +6,7 @@ Though [Liquid][sl] is platform-independent, there're [certain differences][diff
 
 ## The Truth Table
 
-According to [Shopify document](https://shopify.github.io/liquid/basics/truthy-and-falsy/) everything other than `false` and `nil` is truthy. But in JavaScript we have a totally different type system, we have types like `undefined` and we don't differentiate `integer` and `float`, thus things are slightly different:
+According to [Shopify document](https://shopify.github.io/liquid/basics/truthy-and-falsy/) everything other than `false` and `null` is truthy. But in JavaScript we have a totally different type system, we have types like `undefined` and we don't differentiate `integer` and `float`, thus things are slightly different:
 
 value          | truthy | falsy
 ---            | ---    | ---
@@ -24,7 +24,7 @@ value          | truthy | falsy
 
 ## Use JavaScript Truthy
 
-Note that liquidjs use Shopify's truthiness by default. But it can be toggled to used standard JavaScript truthiness by setting the **jsTruthy** option to `true`.
+Note that liquidjs use Shopify's truthiness by default. But it can be toggled to use standard JavaScript truthiness by setting the **jsTruthy** option to `true`.
 
 value          | truthy | falsy
 ---            | ---    | ---
@@ -43,4 +43,4 @@ value          | truthy | falsy
 
 [ruby]: https://shopify.github.io/liquid
 [sl]: https://www.npmjs.com/package/liquidjs
-[diff]: https://github.com/harttle/liquidjs#differences-and-limitations
+[diff]: https://github.com/harttle/liquidjs#differences-and-limitations