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
* Keywords need to still be recognized if they're followed by ',' as well as a bunch of other operator characters. Notably missing from this list is '-', since that would mess up expect-fx currently.
* Smattering of niche cases of formatting bugs (either non-idempotency, leading to different code, or leading to unparsable code)
* One missing indent call in fmt_collection leading to a panic
