NPE on specific regex

[ludovicianul]

Describe the bug I get a NPE with the following regex ^[^\p{C}\p{Z}\s]*[^\p{C}]+[^\p{C}\p{Z}]*$ which didn't happen on version 1.4.

To Reproduce Steps to reproduce the behavior:

1. regex: ^[^\p{C}\p{Z}\s]*[^\p{C}]+[^\p{C}\p{Z}]*$
2. RgxGen.parse("^[^\\p{C}\\p{Z}\\s]*[^\\p{C}]+[^\\p{C}\\p{Z}]*$").generate()
3. See error below

	at com.github.curiousoddman.rgxgen.nodes.SymbolSet.ofUnicodeCharacterClass(SymbolSet.java:72)
	at com.github.curiousoddman.rgxgen.parsing.dflt.DefaultTreeBuilder.createUnicodeSymbolSetNode(DefaultTreeBuilder.java:463)
	at com.github.curiousoddman.rgxgen.parsing.dflt.DefaultTreeBuilder.handleEscapedCharacter(DefaultTreeBuilder.java:410)
	at com.github.curiousoddman.rgxgen.parsing.dflt.DefaultTreeBuilder.handleBackslashInsideSquareBrackets(DefaultTreeBuilder.java:671)
	at com.github.curiousoddman.rgxgen.parsing.dflt.DefaultTreeBuilder.handleSquareBrackets(DefaultTreeBuilder.java:631)
	at com.github.curiousoddman.rgxgen.parsing.dflt.DefaultTreeBuilder.parseGroup(DefaultTreeBuilder.java:228)
	at com.github.curiousoddman.rgxgen.parsing.dflt.DefaultTreeBuilder.build(DefaultTreeBuilder.java:732)
	at com.github.curiousoddman.rgxgen.parsing.dflt.DefaultTreeBuilder.get(DefaultTreeBuilder.java:741)
	at com.github.curiousoddman.rgxgen.RgxGen.<init>(RgxGen.java:65)
	at com.github.curiousoddman.rgxgen.RgxGen.parse(RgxGen.java:59)
	at com.github.curiousoddman.rgxgen.RgxGen.parse(RgxGen.java:48)

Expected behavior Property generate a value.

Environment (please complete the following information):

• MacOS
• JDK 21
• RgxGen Version 2.0

Additional context It works with RgxGen 1.4.