BigInt enhancement: make std.math.abs work with BigInt (issue 6486)
BigInt enhancement: add opCast!bool to BigInt (issue 4120)
[comments] Remove old commented out code in `std.json`.
[whitespace] Fix spaces in `std.json`.
[styling] Put open bracket on its own line in `std.json`.
[refactoring] Minor refactoring of `std.json`.
Merge pull request #1236 from Safety0ff/bigintenh

BigInt enhancements: add opCast!bool and make std.math.abs work
Merge pull request #1206 from denis-sh/std.json-improvements-1

`std.json` refactoring