Enhance parameter help

[decaprime]

• Adds enum values to help command
• IConverterUsage can be implemented for converters to specify a usage string in this interface - this is designed to allow for dynamic values and is expected you'd cache state as much as possible.
• Updates tests to cover above
• Updates pagination to perform splitting, previously only worked when split by lines. Long lists of enum values surfaced this, but it makes the utility function more as expected.