Fix docstring indentation in SaveImage (#7913)

### Description

The docstring for `monai.transforms.io.array.SaveImage` had some faulty
indentation, causing weirdly formatted documentation on the website.
This pull request fixes the indentation.

### Types of changes
<!--- Put an `x` in all the boxes that apply, and remove the not
applicable items -->
- [x] Non-breaking change (fix or new feature that would not break
existing functionality).
- [x] In-line docstrings updated.
- [ ] Documentation updated, tested `make html` command in the `docs/`
folder.

Signed-off-by: Mathijs de Boer <m.deboer-41@umcutrecht.nl>
Co-authored-by: Mathijs de Boer <m.deboer-41@umcutrecht.nl>

monai/transforms/io/array.py

@@ -307,11 +307,11 @@ class SaveImage(Transform):
 
     Args:
         output_dir: output image directory.
-        Handled by ``folder_layout`` instead, if ``folder_layout`` is not ``None``.
+            Handled by ``folder_layout`` instead, if ``folder_layout`` is not ``None``.
         output_postfix: a string appended to all output file names, default to `trans`.
-        Handled by ``folder_layout`` instead, if ``folder_layout`` is not ``None``.
+            Handled by ``folder_layout`` instead, if ``folder_layout`` is not ``None``.
         output_ext: output file extension name.
-        Handled by ``folder_layout`` instead, if ``folder_layout`` is not ``None``.
+            Handled by ``folder_layout`` instead, if ``folder_layout`` is not ``None``.
         output_dtype: data type (if not None) for saving data. Defaults to ``np.float32``.
         resample: whether to resample image (if needed) before saving the data array,
             based on the ``"spatial_shape"`` (and ``"original_affine"``) from metadata.