Update readme with punctuation examples

[jncasey]

Here's a small update to the readme with some examples around punctuation marks (both the new regex version and the original string version). I meant to include this with my last PR, but it slipped my mind. It looks like this might clear up a few open issues.

Also caught a few typos.

[codecov[bot]]

Codecov Report

Merging #121 (c5c02d0) into master (2667235) will not change coverage. The diff coverage is n/a.

@@            Coverage Diff            @@
##            master      #121   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files           23        23           
  Lines         1184      1184           
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  Hits          1184      1184           

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[mmmaat]

Thank you!