* Fraction Formatting
See issue #2253. User's analysis was correct - leading zeros in the decimal portion were being stripped out, so 0.0625 and 0.625 were being treated the same. As it turns out, integers also aren't handled well (`0 0/1` anyone?). The latter problem had been hidden because caller tested for integer first and skipped call if true; but FractionFormatter::format is public and should work correctly regardless. All Phpstan baseline entries for FractionFormatter and NumberFormatter are eliminated. New test data is added; no need for changes to test code.
* Scrutinizer
Ensure result is string.