FIX: fix typo (#278)

Co-authored-by: Gu Lee <99sphere@gmai.com>

nerfacc/estimators/occ_grid.py

@@ -123,9 +123,9 @@ def sampling(
             near_plane: Optional. Near plane distance. Default: 0.0.
             far_plane: Optional. Far plane distance. Default: 1e10.
             t_min: Optional. Per-ray minimum distance. Tensor with shape (n_rays).
-                If profided, the marching will start from maximum of t_min and near_plane.
+                If provided, the marching will start from maximum of t_min and near_plane.
             t_max: Optional. Per-ray maximum distance. Tensor with shape (n_rays).
-                If profided, the marching will stop by minimum of t_max and far_plane.
+                If provided, the marching will stop by minimum of t_max and far_plane.
             render_step_size: Step size for marching. Default: 1e-3.
             early_stop_eps: Early stop threshold for skipping invisible space. Default: 1e-4.
             alpha_thre: Alpha threshold for skipping empty space. Default: 0.0.