Update README.md (#13283)

* Update README.md

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* Auto-format by https://ultralytics.com/actions

---------

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>
Co-authored-by: UltralyticsAssistant <web@ultralytics.com>

utils/plots.py

@@ -81,7 +81,7 @@ def feature_visualization(x, module_type, stage, n=32, save_dir=Path("runs/detec
     module_type:    Module type
     stage:          Module stage within model
     n:              Maximum number of feature maps to plot
-    save_dir:       Directory to save results
+    save_dir:       Directory to save results.
     """
     if ("Detect" not in module_type) and (
         "Segment" not in module_type