Update action.Rmd (#502)

Author: bm5tev3

action.Rmd

@@ -12,7 +12,7 @@ Here's a quick run down of the main topics:
 
 -   Chapter \@ref(action-graphics) shows you how to add direct interaction to your plot and how to display images generated in other ways.
 
--   Chapter \@ref(action-feedback) covers a family of techniques (including inline errors, notifications, progress bars, and dialog boxes) for giving feedback to your users while you app runs.
+-   Chapter \@ref(action-feedback) covers a family of techniques (including inline errors, notifications, progress bars, and dialog boxes) for giving feedback to your users while your app runs.
 
 -   Chapter \@ref(action-transfer) discusses how to transfer files to and from your app.