Apply black to _hog.py (#7215)

#7153 was merged previously and didn't yet include the most recent
changes from main yet which introduced the black pre-commit hook. So
for a while we'll need to make sure that we merge `main` before
merging.

skimage/feature/_hog.py

@@ -311,10 +311,12 @@ def hog(
     if n_blocks_col <= 0 or n_blocks_row <= 0:
         min_row = b_row * c_row
         min_col = b_col * c_col
-        raise ValueError('The input image is too small given the values of '
-                         'pixels_per_cell and cells_per_block. '
-                         'It should have at least: '
-                         f'{min_row} rows and {min_col} cols.')
+        raise ValueError(
+            'The input image is too small given the values of '
+            'pixels_per_cell and cells_per_block. '
+            'It should have at least: '
+            f'{min_row} rows and {min_col} cols.'
+        )
     normalized_blocks = np.zeros(
         (n_blocks_row, n_blocks_col, b_row, b_col, orientations), dtype=float_dtype
     )

skimage/feature/tests/test_hog.py

@@ -353,4 +353,8 @@ def test_hog_small_image():
 
     img = np.zeros((23, 23))
     with pytest.raises(ValueError, match=".*image is too small given"):
-        feature.hog(img, pixels_per_cell=(8, 8), cells_per_block=(3, 3),)
+        feature.hog(
+            img,
+            pixels_per_cell=(8, 8),
+            cells_per_block=(3, 3),
+        )