[datasets] fix description

[felixdittrich92]

minor description improvements

[codecov]

Codecov Report

Merging #795 (564161c) into main (0da7ce0) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #795   +/-   ##
=======================================
  Coverage   96.03%   96.03%           
=======================================
  Files         131      131           
  Lines        4942     4942           
=======================================
  Hits         4746     4746           
  Misses        196      196           

Flag	Coverage Δ
unittests	96.03% <ø> (ø)

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

Impacted Files	Coverage Δ
doctr/datasets/detection.py	95.65% <ø> (ø)
doctr/datasets/ic13.py	96.15% <ø> (ø)
doctr/datasets/imgur5k.py	92.50% <ø> (ø)
doctr/datasets/loader.py	100.00% <ø> (ø)
doctr/datasets/ocr.py	92.30% <ø> (ø)
doctr/datasets/recognition.py	80.95% <ø> (ø)
doctr/transforms/modules/base.py	94.59% <0.00%> (ø)

---

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 0da7ce0...564161c. Read the comment docs.

[fg-mindee]

Thanks!