Print tokens as their name in parser

[JSAbrahams]

Relevant issues

Resolves #217

At least, I think it addresses what that issue said. It was written a bit vague.

Summary

• Add some hints for what level of operation crashed. This is more to ease development, since they won't say much to an end-user. Come to think of it, the parser goes on longer than it should here so errors aren't that helpful.
• If no reference tokens, just say 'a token'.

Added Tests

None

[codecov[bot]]

Codecov Report

:exclamation: No coverage uploaded for pull request base (develop@da1685c). Click here to learn what that means. The diff coverage is n/a.

@@            Coverage Diff             @@
##             develop     #235   +/-   ##
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  Coverage           ?   79.69%           
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  Files              ?       99           
  Lines              ?     8624           
  Branches           ?        0           
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  Hits               ?     6873           
  Misses             ?     1751           
  Partials           ?        0           

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