Improve the "did you mean" suggestions for booleans

[eminence]

If you misspell true or false, you get weird "did you mean" suggestions:

>>> 4 > 5 == False
error: while type checking
  ┌─ <input:7>:1:10
  │
1 │ 4 > 5 == False
  │          ^^^^^ unknown identifier
  │
  = Did you mean 'floz'?

This is because true and false are keywords, not identifiers, so the "did you mean" code doesn't consider them.

This small patch appends both values to the list sent to did_you_mean().

An alternative way to fix this (arguably a better way) would be to modify the impl ErrorDiagnostic for TypeCheckError to check for other suggestions on a TypeCheckError::UnknownIdentifier error

[sharkdp]

Thank you very much for your contribution!

An alternative way to fix this (arguably a better way) would be to modify the impl ErrorDiagnostic for TypeCheckError to check for other suggestions on a TypeCheckError::UnknownIdentifier error

I think I like your way better. Keeps the diagnostic modules' purpose focused on laying out errors in a nice way (without worrying about the contents of the error).

[sharkdp]

Changes are live on https://numbat.dev: https://numbat.dev/?q=assert((1%20yard%20%3E%201%20meter)%20==%20False)