Update adding-custom-endpoints.md

Grammatical Corrections

Author: andrewl64

extending-the-rest-api/adding-custom-endpoints.md

@@ -2,7 +2,7 @@
 
 The WordPress REST API is more than just a set of default routes. It is also a tool for creating custom routes and endpoints. The WordPress front-end provides a default set of URL mappings, but the tools used to create them (e.g. the Rewrites API, as well as the query classes: `WP_Query`, `WP_User`, etc) are also available for creating your own URL mappings, or custom queries.
 
-This document details how to create a totally custom route, with its own endpoints. We'll first work through a short example, then expand it out to the full controller pattern as used internally.
+This document details how to create a new and completely custom route with its own endpoints. We'll first work through a short example and then expand it out to the full controller pattern as used internally.
 
 
 ## Bare Basics