Breaking but unimportant changes

[alexpovel]

These could be collected and then released all at once, to reduce churn and have a single "BREAKING CHANGES" section in a single release.

• --stdin-override-to is currently Option<bool> which is stupid and confusing. It should be its own enum along the lines of

  enum StdinPresence {
      Heuristic, // previously `None`
      ForceOn, // previously `Some(true)`
      ForceOff, // previously `Some(false)`
  }

  which would read much neater on the CLI and also be less of a headache to understand ("what does None mean again?")

[issuedigger]

The most similar issues to this one are:

1. 0.13.0 build failure #106 , with a similarity score of 0.93.
2. Fix cloning static query on every query call #76 , with a similarity score of 0.91.
3. Implement language grammars #48 , with a similarity score of 0.91.

[alexpovel]

Relates to #149