* Improved integer and floating point `formatted()` methods.
- [IntegerFormatStyle] I removed the trapping conversion to `Int`. IntegerFormatStyle can format big integers since (#262).
- [FloatingPointFormatStyle] I removed the rounding conversion to `Double`. `formatted()` now does whatever `format(_:)` does.
- [Decimal.FormatStyle] N/A (there were no conversions here).
* Reenabled "Decimal Tests" in NumberFormatStyleTests.swift.
- IntegerFormatStyle big integer tests succeed.
- IntegerFormatStyle.Attributed big integer tests fail (output is clamped to `Int64`).
* Fixes IntegerFormatStyle.Attributed.
- Added a numeric string representation case to ICUNumberFormatter.Value.
- IntegerFormatStyle.Attributed now uses the above instead of `Int64(clamping:)`.
* Removed conversions to Decimal in each integer format style (#186).
BinaryInteger's numeric string representation supersedes Decimal in the following cases:
1. IntegerFormatStyle.
2. integerFormatStyle.Attributed.
3. IntegerFormatStyle.Currency.
4. IntegerFormatStyle.Percent.
* Check whether numeric string is zero using Double.
The numeric string format permits redundant zeros (like `+00.00`).
* Removed `isZero` and `doubleValue` from `ICUNumberFormatter.Value`.
Both `isZero` and `doubleValue` were used in `ByteCountFormatStyle`. These values are now taken from `FormatInput` (`Int64`) instead. Removing them from `ICUNumberFormatter.Value` makes it easier to accommodate non-numeric payloads such as strings, which can be used to format arbitrary precision numbers.
* Added `_format(_:doubleValue:)` to `ByteCountFormatStyle`.
Here's an internal method simliar to the `_format(_:)` method removed earlier because wants its method back! I removed the first method to accommodate `ICUNumberFormatter.Value` cases that cannot implement `doubleValue`. The new method parameterizes the conversion instead, so you can call it whenever conversions to `Double` are possible.
