Create an auto-formatter

[Aloso]

Is your feature request related to a problem? Please describe.

There is currently no way to automatically format a pomsky expression.

Describe the solution you'd like

A tool, part of pomsky-bin, that accepts several configuration options similar to prettier, parses a pomsky expression losslessly (preserving comments and whitespace), and returns a pomsky expression that is beautifully formatted, without changing its semantic meaning. Here are some things it can do:

• Add/remove white space
• Add/remove a leading pipe
• Remove unnecessary parentheses
• Convert double quotes to single quotes or vice versa
• Simplify repetitons (e.g. {1,} -> +)
• Wrap comments
• Replace deprecated syntax

Things it can not (or should not) do:

• Do anything that changes what the expression can match
• Rename identifiers
• Remove or reorder comments
• Reorder alternatives or character set contents
• Remove unreachable expressions