fix typos and spelling errors

[ghost]

Fixing some minor spelling errors which should not affect functionality but improve the overall quality of documentation.

[antagomir]

Very nice, thank you so much @random415 !

[codecov[bot]]

Codecov Report

Merging #265 (0147957) into master (a1c1459) will not change coverage. The diff coverage is n/a.

:exclamation: Current head 0147957 differs from pull request most recent head 2678f52. Consider uploading reports for the commit 2678f52 to get more accurate results

@@           Coverage Diff           @@
##           master     #265   +/-   ##
=======================================
  Coverage   67.18%   67.18%           
=======================================
  Files          24       24           
  Lines        1024     1024           
=======================================
  Hits          688      688           
  Misses        336      336