Copy edit AT_CellularBase.h

Copy edit file for clarified phrasing.

Author: Amanda Butler

features/cellular/framework/AT/AT_CellularBase.h

@@ -37,10 +37,10 @@ class AT_CellularBase
      */
     ATHandler& get_at_handler();
 
-    /** Gets the device error which happened when using AT commands/responses. This is at error
+    /** Gets the device error that happened when using AT commands/responses. This is at error
      *  returned by the device. Returned CME/CMS errors can be found from 3gpp documents 27007 and 27005.
      *
-     *  @return at error (CME/CMS) while communication with the device
+     *  @return at error (CME/CMS) while communicating with the device
      */
     device_err_t get_device_error() const;