Corrected a few Doxygen documentation errors.

src/gravity_cache.h

@@ -128,6 +128,7 @@ static INLINE void gravity_cache_init(struct gravity_cache *c, int count) {
  * @param gcount_padded The number of particle to read padded to the next
  * multiple of the vector length.
  * @param shift A shift to apply to all the particles.
+ * @param cell The cell the #gpart are in.
  */
 __attribute__((always_inline)) INLINE void gravity_cache_populate(
     struct gravity_cache *c, const struct gpart *restrict gparts, int gcount,

src/runner_doiact_vec.c

@@ -243,14 +243,12 @@ __attribute__((always_inline)) INLINE static void storeInteractions(
  * @param di_max Maximal position on the axis that can interact in cell ci
  * @param dj_min Minimal position on the axis that can interact in cell ci
  * @param max_index_i array to hold the maximum distances of pi particles into
- * cell
- * cj
+ * #cell cj
  * @param max_index_j array to hold the maximum distances of pj particles into
- * cell
- * cj
+ * #cell cj
  * @param init_pi first pi to interact with a pj particle
  * @param init_pj last pj to interact with a pi particle
- * @param e The #engine.
+ * @param max_active_bin The largest time-bin active during this step.
  */
 __attribute__((always_inline)) INLINE static void populate_max_index_no_cache(
     const struct cell *ci, const struct cell *cj,