Rewrite shortened type printer to use refined / plain printer methods

[rochala]

Compiler version

3.5.0

Minimized code

Shortened type printer has a technical debt of custom methods handling printing of signatures.
This causes a lot of problems with label printing. This should be rewritten to reuse methods provided by RefinedPrinter / PlainPrinter such as showDcl

https://github.com/scala/scala3/blob/4bd33693ba759fe67437117f77bf6e5ddf3b7cf0/presentation-compiler/src/main/dotty/tools/pc/printer/ShortenedTypePrinter.scala