Documented the new mulx-based mixing algorithm

[cppalliance-bot]

An automated preview of the documentation is available at https://181.unordered.prtest.cppalliance.org/libs/unordered/doc/html/unordered.html

[codecov[bot]]

Codecov Report

Merging #181 (14d8072) into develop (a74962b) will not change coverage. The diff coverage is n/a.

Additional details and impacted files

[](https://codecov.io/gh/boostorg/unordered/pull/181?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=boostorg) ```diff @@ Coverage Diff @@ ## develop #181 +/- ## ======================================== Coverage 97.72% 97.72% ======================================== Files 85 85 Lines 12720 12720 ======================================== Hits 12431 12431 Misses 289 289 ``` ------ [Continue to review full report at Codecov](https://codecov.io/gh/boostorg/unordered/pull/181?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://codecov.io/gh/boostorg/unordered/pull/181?src=pr&el=footer&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=boostorg). Last update [a74962b...14d8072](https://codecov.io/gh/boostorg/unordered/pull/181?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).