libcamera: Remove extra ':' after '\todo'

The doxygen '\todo' directory doesn't need to be followed by a colon,
yet a few strayed occurrences have made their way in. Fix them.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>

src/libcamera/request.cpp

@@ -349,7 +349,7 @@ Request::Request(Camera *camera, uint64_t cookie)
 				    camera->_d()->validator());
 
 	/**
-	 * \todo: Add a validator for metadata controls.
+	 * \todo Add a validator for metadata controls.
 	 */
 	metadata_ = new ControlList(controls::controls);