Add missing argument description.

src/api/step_launch.c

@@ -93,8 +93,8 @@ static struct io_operations message_socket_ops = {
  * slurm_job_step_launch_t_init - initialize a user-allocated
  *      slurm_job_step_launch_t structure with default values.
  *	default values.  This function will NOT allocate any new memory.
- * IN ptr - pointer to a structure allocated by the use.  The structure will
- *      be intialized.
+ * IN ptr - pointer to a structure allocated by the user.
+ *      The structure will be intialized.
  */
 void slurm_job_step_launch_t_init (slurm_job_step_launch_t *ptr)
 {
@@ -128,6 +128,7 @@ void slurm_job_step_launch_t_init (slurm_job_step_launch_t *ptr)
 /*
  * slurm_step_launch - launch a parallel job step
  * IN ctx - job step context generated by slurm_step_ctx_create
+ * IN callbacks - Identify functions to be called when various events occur
  * RET SLURM_SUCCESS or SLURM_ERROR (with errno set)
  */
 int slurm_step_launch (slurm_step_ctx ctx,