Use floff to consistently generate correctly rounded results

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (bef2775) 92.17% compared to head (3293512) 92.30%.

Additional details and impacted files

[](https://app.codecov.io/gh/boostorg/charconv/pull/164?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=boostorg) ```diff @@ Coverage Diff @@ ## develop #164 +/- ## =========================================== + Coverage 92.17% 92.30% +0.12% =========================================== Files 64 64 Lines 8321 8316 -5 =========================================== + Hits 7670 7676 +6 + Misses 651 640 -11 ``` | [Files](https://app.codecov.io/gh/boostorg/charconv/pull/164?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=boostorg) | Coverage Δ | | |---|---|---| | [include/boost/charconv/detail/dragonbox/floff.hpp](https://app.codecov.io/gh/boostorg/charconv/pull/164?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=boostorg#diff-aW5jbHVkZS9ib29zdC9jaGFyY29udi9kZXRhaWwvZHJhZ29uYm94L2Zsb2ZmLmhwcA==) | `73.60% <100.00%> (+0.85%)` | :arrow_up: | ------ [Continue to review full report in Codecov by Sentry](https://app.codecov.io/gh/boostorg/charconv/pull/164?src=pr&el=continue&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=boostorg). > **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=boostorg) > `Δ = absolute (impact)`, `ø = not affected`, `? = missing data` > Powered by [Codecov](https://app.codecov.io/gh/boostorg/charconv/pull/164?src=pr&el=footer&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=boostorg). Last update [bef2775...3293512](https://app.codecov.io/gh/boostorg/charconv/pull/164?src=pr&el=lastupdated&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=boostorg). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=boostorg).