Fix typo in anti-pitch (react-navigation#294)

* Fix typo in anti-pitch

* Typo fix

Author: javogel

docs/pitch.md

@@ -18,6 +18,6 @@ It's useful when considering whether or not to use a project to understand the t
 ## Anti-pitch
 
 - The API is sometimes unintuitive and difficult to use, improvements may require breaking changes. We are working to make ["easy things easy and hard things possible"](https://www.quora.com/What-is-the-origin-of-the-phrase-make-the-easy-things-easy-and-the-hard-things-possible) and this may require us to change the API at times.
-- React Navigation does not directly use the native navigation APIs on iOS and Android; rather, it re-creates some subset of those APIs. This a conscious choice in order to make it possible for users to customize any part of the navigation experience (because it's implemented in JavaScript) and to be able to debug issues that they encounter without needing to learn Objective C / Swift / Java / Kotlin.
+- React Navigation does not directly use the native navigation APIs on iOS and Android; rather, it re-creates some subset of those APIs. This is a conscious choice in order to make it possible for users to customize any part of the navigation experience (because it's implemented in JavaScript) and to be able to debug issues that they encounter without needing to learn Objective C / Swift / Java / Kotlin.
   - If you need the exact platform behavior you are better off using another library that wraps the platform APIs. Read more about these in [Alternatives](alternatives.html) and be sure to understand the tradeoffs that they make before digging in!
 - Because much of the logic for React Navigation runs in JavaScript rather than in native, the usual concerns about blocking the JavaScript thread come into play.

website/versioned_docs/version-1.x/pitch.md

@@ -19,6 +19,6 @@ It's useful when considering whether or not to use a project to understand the t
 ## Anti-pitch
 
 - The API is sometimes unintuitive and difficult to use, improvements may require breaking changes. We are working to make ["easy things easy and hard things possible"](https://www.quora.com/What-is-the-origin-of-the-phrase-make-the-easy-things-easy-and-the-hard-things-possible) and this may require us to change the API at times.
-- React Navigation does not directly use the native navigation APIs on iOS and Android; rather, it re-creates some subset of those APIs. This a conscious choice in order to make it possible for users to customize any part of the navigation experience (because it's implemented in JavaScript) and to be able to debug issues that they encounter without needing to learn Objective C / Swift / Java / Kotlin.
+- React Navigation does not directly use the native navigation APIs on iOS and Android; rather, it re-creates some subset of those APIs. This is a conscious choice in order to make it possible for users to customize any part of the navigation experience (because it's implemented in JavaScript) and to be able to debug issues that they encounter without needing to learn Objective C / Swift / Java / Kotlin.
   - If you need the exact platform behavior you are better off using another library that wraps the platform APIs. Read more about these in [Alternatives](alternatives.html) and be sure to understand the tradeoffs that they make before digging in!
 - Because much of the logic for React Navigation runs in JavaScript rather than in native, the usual concerns about blocking the JavaScript thread come into play.