Support dX dice shorthand

[lyrae-versebound]

Summary

• Accept dice shorthand such as dX by treating a leading d as an implicit single-die operand.
• Preserve parser operand state so shorthand works correctly around closing parentheses and whitespace.
• Add regression coverage for shorthand and the related parser transitions.

Validation

• Focused tests: 19/19.
• Neighboring parser tests: 22/22.
• Complete GoRogue.UnitTests: 1326/1326 in Debug.
• Complete GoRogue.UnitTests: 1326/1326 in Release.

Fixes #337

[Chris3606]

Thanks! I'm on vacation at the moment but hopefully can get to looking at this in detail in a couple days.

[lyrae-versebound]

Thanks! Just trying to give a little back to projects we’ve used and appreciated. No rush at all — take a look whenever you get a chance! 🙂