Fix up documentation

src/cell.c

@@ -899,6 +899,7 @@ int cell_is_drift_needed(struct cell *c, int ti_current) {
  * if the space needs to be rebuilt.
  *
  * @param c the #cell.
+ * @param s the #scheduler.
  *
  * @return 1 If the space needs rebuilding. 0 otherwise.
  */

src/runner.c

@@ -747,10 +747,13 @@ void runner_do_ghost(struct runner *r, struct cell *c) {
 }
 
 /**
- * @brief Drift particles and g-particles in a cell forward in time
+ * @brief Drift particles and g-particles in a cell forward in time,
+ *              unskipping any tasks associated with active cells.
  *
  * @param c The cell.
  * @param e The engine.
+ * @param drift whether to actually drift the particles, will not be
+ *              necessary for non-local cells.
  */
 static void runner_do_drift(struct cell *c, struct engine *e, int drift) {