Doc, Test Fixes in Normalize

[surgan12]

This PR fixes the doc for normalize transform and also adds a test case for the same.
cc: @fmassa

[codecov-io]

Codecov Report

Merging #1063 into master will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1063      +/-   ##
==========================================
+ Coverage   63.95%   63.97%   +0.01%     
==========================================
  Files          66       66              
  Lines        5279     5279              
  Branches      793      793              
==========================================
+ Hits         3376     3377       +1     
  Misses       1672     1672              
+ Partials      231      230       -1

Impacted Files	Coverage Δ
torchvision/transforms/transforms.py	82.12% <ø> (ø)	⬆️
torchvision/transforms/functional.py	72.27% <ø> (+0.29%)	⬆️

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[fmassa]

Thanks!