Update alignment with ultralytics docs

[zhiqwang]

This is a follow-up PR of #120.

[review-notebook-app]

Check out this pull request on 

See visual diffs & provide feedback on Jupyter Notebooks.

---

Powered by ReviewNB

[codecov]

Codecov Report

Merging #121 (49cb27c) into master (7b20f38) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #121   +/-   ##
=======================================
  Coverage   83.54%   83.54%           
=======================================
  Files           8        8           
  Lines         784      784           
=======================================
  Hits          655      655           
  Misses        129      129           

Flag	Coverage Δ
unittests	83.54% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 7b20f38...49cb27c. Read the comment docs.