Fix typos in documentation and code comments

Author: OskarStark

CHANGELOG.md

@@ -706,7 +706,7 @@ CHANGELOG
  * added Client::enableProfiler()
  * a new parameter has been added to the DIC: `router.request_context.base_url`
    You can customize it for your functional tests or for generating URLs with
-   the right base URL when your are in the CLI context.
+   the right base URL when you are in the CLI context.
  * added support for default templates per render tag
 
 2.1.0