This is consistent with `JSON.parse("-0")` in JavaScript, RFC 8259
doesn't specifically mention what to do in this case.
If a negative zero is encoded the intention is likely to preserve the
sign.
* std.unicode: Add more UTF-16 decoding functions
This mostly makes parts of Utf16LeIterator reusable
* std.json: Fix decoding of UTF-16 surrogate pairs
Before this commit, there were 524,288 codepoints that would get decoded improperly. After this commit, there are 0.
Fixes#16828
Most of this migration was performed automatically with `zig fmt`. There
were a few exceptions which I had to manually fix:
* `@alignCast` and `@addrSpaceCast` cannot be automatically rewritten
* `@truncate`'s fixup is incorrect for vectors
* Test cases are not formatted, and their error locations change
