bugfix division by zero

[Ousret]

close #22

[codecov-io]

Codecov Report

Merging #23 into master will increase coverage by 0.09%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #23      +/-   ##
==========================================
+ Coverage   83.13%   83.23%   +0.09%     
==========================================
  Files          13       13              
  Lines         854      859       +5     
==========================================
+ Hits          710      715       +5     
  Misses        144      144

Impacted Files	Coverage Δ
charset_normalizer/normalizer.py	83.19% <100%> (+0.21%)	⬆️
charset_normalizer/probe_chaos.py	81.87% <100%> (+0.21%)	⬆️

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[Ousret]

when explain is set to True we can see that utf-16 codec can decode content with two bytes and therefore produce a zero-length str.
Maybe it is a bug.