Update README.md

Author: remcoder

README.md

@@ -5,7 +5,7 @@ Enriches the file list with a preview thumbnail for each gcode file.
 ![image](https://user-images.githubusercontent.com/461650/58376079-2ec9a400-7f62-11e9-85e0-f48329dabb2c.png)
 
 ## Use at your own risk
-This plugin uses some hack to what is otherwise impossible via the official API. This means that upgrading Octoprint or using other plugins will lead to all sorts of issues.
+This plugin uses some hacks to do what is otherwise impossible via the official API. This means that upgrading Octoprint or using other plugins will lead to all sorts of issues.
 
 ## Setup