Update chapter11.md

Small recommendations to improve readability.

manuscript/chapter11.md

@@ -4,20 +4,20 @@ Now that you've discovered the basics of programming, let's go ahead and build a
 
 ## Objective
 
-The goal of this project is to build a basic social news program. Its user will be able to show a list of links and add new ones.
+The goal of this project is to build a basic social news program. Its users will be able to show a list of links and add new ones.
 
 ## Functional requirements
 
 * A link is defined by its title, its URL and its author (submitter).
-* If a new link URL does not start with `"http://"` or `"https://"`, `"http://"` is automatically added at its beginning.
+* If a new link URL does not start with `"http://"` or `"https://"`, `"http://"` is automatically added to its beginning.
 * At launch, the program displays a start menu with the possible actions in an alert window and asks the user for his choice. Possible actions are:
   * Show the list of links.
   * Add a new link.
   * Remove an existing link.
   * Quit the program.
 * Showing the list of links displays the index (rank) and the properties of each link in an alert window, or a message in the absence of any link.
-* When adding a link, the program asks the user for the new link properties (title, URL and author). The link is then created. Subsequently, it must appear in the showed links.
-* When removing a link, the user is asked for the link index until it is correct. The associated link is then removed. Subsequently, it must disappear from the showed links. Removing a link is not possible if there are no existing links.
+* When adding a link, the program asks the user for the new link properties (title, URL and author). The link is then created. Subsequently, it must appear in the shown links.
+* When removing a link, the user is asked for the link index until it is correct. The associated link is then removed. Subsequently, it must disappear from the shown links. Removing a link is not possible if there are no existing links.
 * After an action is performed, the start menu is shown again. This goes on until the user chooses to quit the program.
 
 ## Technical requirements
@@ -34,4 +34,4 @@ Here are a few screenshots of the expected result.
 
 ![Showing a link](images/chapter11-02.png)
 
-![Selecting a link index](images/chapter11-03.png)
+![Selecting a link index](images/chapter11-03.png)