bug: tag literals

[oakmac]

An alpha testing user found a bug while formatting Aero EDN files. Looks like it involves the # character. Need to investigate and create a minimal test case.

[oakmac]

Basic support added with PR-72.

Going to leave this issue open because we probably need to add some more test cases for tagged literals.

[oakmac]

I asked @shaunlebron to help out with this:

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I took a quick look:

1. tagged literals seem to be just a symbol followed by any form.
2. luckily the formatter doesn’t have to care about anything other than reading the literal symbol and subsequent form, so we can ignore all the subtleties around evaluating them.
3. I see your parser and format tests for tags seem to be working fine.
4. I can’t think of any special formatting rules it should have, except for maybe removing any potential spaces between the # and symbol, since # inst "2024-09-26" is allowed. All other considerations should probably be handled by the existing rules for the literal types.

[oakmac]

Closing this for now; we can re-open if another breaking case is discovered.