Fix a documentation typo

[DNNX]

Drive-by typo fix. Cheers!

[codecov]

Codecov Report

Merging #198 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #198   +/-   ##
=======================================
  Coverage   96.01%   96.01%           
=======================================
  Files          23       23           
  Lines         452      452           
=======================================
  Hits          434      434           
  Misses         18       18

Impacted Files	Coverage Δ
lib/tesla/middleware/logger.ex	87.8% <ø> (ø)	⬆️

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