Add `std.traits.{isNested,hasNested}`.
Fix `std.traits.FieldTypeTuple` for structs.
Document what exactly `std.traits.FieldTypeTuple` do.
Fix issue 4909
[whitespace] Fix spaces in `std.math.FloatingPointControl` example and unittest.
Fix `std.math.FloatingPointControl` two issues.

1. Do not call `setControlState` in destructor if not initialized (previously results in enabling all exceptions).
2. Call `initialize` on setting rounding mode (previously not called).
[docs] Improve `std.math.FloatingPointControl` example.
Merge pull request #1197 from andralex/4909

Fix issue 4909 - Two suggestions for std.algorithm.schwartzSort()
tweak in scoped
Fixes Issue 9794 - std.json cannot handle delete character
Merge pull request #1218 from monarchdodra/scoped2

tweak in scoped
Merge pull request #1219 from jacob-carlborg/issue_9794

Fixes Issue 9794 - std.json cannot handle delete character
Merge pull request #948 from denis-sh/add-traits-for-nested-structs

Add `std.traits.{isNested,hasNested}`.
Merge pull request #1208 from denis-sh/std.math.FloatingPointControl-fixes

`std.math.FloatingPointControl` fixes