Amend documentation to prefer match_array over =~

Update operators feature to refer to match_array instead of =~ operator
and added additional examples to READMEs to surface the existence of
match_array
Update the wording for recommending the use of match_array

Fix another typo in the preceding sentence
Merge pull request #302 from andyh/document-match-array

Amend documentation to prefer match_array over =~