JSON5 support

[Mechite]

Self explanatory! https://json5.org/

[TheElectronWill]

interesting! thanks for the link

[IMB11]

JSON5 is supported by the Jankson library.

[Mechite]

Just a small comment (and bump) - is there actually much of a difference between JSON5 and HOCON, other than the other features HOCON has? - i.e. isn't all valid JSON5 also valid HOCON? If this is the case, I think we can simply point people to use NightConfig HOCON instead, though I don't know if the writing capabilities of the HOCON parser are going to be adequate for people who wish to use JSON5. JSON5 has many factors that make it attractive, perhaps the main one being that it is all valid JavaScript code, and the ease of enforcing convention on JSON5, where HOCON's ability to use = and omitting commas can be an issue.