Feature request: Hex with two's complement

**Is your feature request related to a problem? Please describe.**

I have some data with strings like `-16777216`, that can be converted to hex as `-FF0100`. But for the sign, we can apply [Two's complements](https://en.wikipedia.org/wiki/Two%27s_complement) to display hex signed 2's complement `FF00FF00` like here: https://www.rapidtables.com/convert/number/decimal-to-hex.html

**Describe the solution you'd like**

See above.

**Describe alternatives you've considered**

https://www.rapidtables.com/convert/number/decimal-to-hex.html

**Additional context**

Sorry, the JSON is from an internal project.

Thanks!

No files or tests are named in the issue. Start by locating the existing decimal-to-hex conversion entry point and inspect how negative values and output width are handled. Clarify the intended two's-complement width and add coverage showing the requested result for -16777216; done means the behavior is documented and tested.

Written by the indexing model from the issue text.