Fixed typo in application-environment.asciidoc (#8546)

organized was already fixed so added This.

documentation/application/application-environment.asciidoc

@@ -45,7 +45,7 @@ we give the instructions for Eclipse.
 The following files are required in a web application in order to run it.
 
 [filename]#WEB-INF/web.xml# (optional with Servlet 3.0)::
- his is the web application descriptor that defines how the application is organized, that is, what servlets and such it has.
+This is the web application descriptor that defines how the application is organized, that is, what servlets and such it has.
 You can refer to any Java book about the contents of this file.
 It is not needed if you define the Vaadin servlet with the [classname]#@WebServlet# annotation in Servlet API 3.0.