Replaced hyphen with em dash

Author: bvaughn

content/blog/2018-03-29-react-v-16-3.md

@@ -47,7 +47,7 @@ We can use the above HOC to wire components up to the theme context without havi
 
 `embed:16-3-release-blog-post/fancy-button-example.js`
 
-HOCs typically [pass props through](/docs/higher-order-components.html#convention-pass-unrelated-props-through-to-the-wrapped-component) to the components they wrap. Unfortunately, [refs are not passed through](/docs/higher-order-components.html#refs-arent-passed-through). This means that we can't attach a ref to `FancyButton` if we use `FancyThemedButton`- so there's no way for us to call `focus()`.
+HOCs typically [pass props through](/docs/higher-order-components.html#convention-pass-unrelated-props-through-to-the-wrapped-component) to the components they wrap. Unfortunately, [refs are not passed through](/docs/higher-order-components.html#refs-arent-passed-through). This means that we can't attach a ref to `FancyButton` if we use `FancyThemedButton`— so there's no way for us to call `focus()`.
 
 The new `forwardRef` API solves this problem by providing a way for us to intercept a `ref` and forward it as a normal prop:
 `embed:16-3-release-blog-post/forward-ref-example.js`