message: Update contracts.dox
  Fixed typo in line 33.  "give" to "given"
diff: }
  ```
  - `apply` is give the arguments `code` and `action` which uniquely identify every event in
  + `apply` is given the arguments `code` and `action` which uniquely identify every event in
  the system. For example, `code` could be a *currency* contract and `action` could be *transfer*. This event (code,action)
  may be passed to several contracts including the `sender` and `receiver`. It is up to your application to figure
  out what to do in response to such an event.
  