Notably:
* Unified how parens are formatted between (1) when we have a ParensAround, and (2) when we've decided an Apply needs to have parens
* Made unary minus require the be indented to the same level as any other expression continuation. (it used to accidentally have rules meant for binary operators applied)
* Don't apply extra indent to the backpassing continuation in the case that the call does itself require indentation
* Make `try@foo` correctly parse as `try @foo`, so that formatting doesn't change the tree when it adds that space
* Detect more cases where we need to outdent trailing e.g. {} blocks in applies
* Approximately a bagillion other things, 90% of which I added tests for, and none of which affected the formatting of examples or builtins
This was never fully hooked up in platforms, and the plan is to replace the need for this with doing purity-inference on normal `expect` statements.
On the other hand, fuzzing is finding some bugs caused by having a hyphenated keyword, so this is a great time to go ahead and remove it!
In order to desugar `dbg` in a pipeline we need to allow a bare `dbg`
node in desugaring and only report it as an error if the bare node
survives to the next step of canonicalization. This means we move the
error code out of `desugar_expr` and into `canonicalize_expr`. This is
much simpler to do now that these functions use the same `env` struct,
since previously we would have had to pass down extra args to
`canonicalize_expr`. Sharing the `env` struct means that we also don't
have to worry about calculating `line_info` more than once.