Janet 1.42.0

As a occasional Janet user, I will offer some constructive criticism on the "What's changed": Let's get some syntax for

Improve docstrings of filter and friends by @sogaiu in #1815

Improve docstrings for each and friends by @sogaiu in #1816

Improve docstrings of reduce and friends by @sogaiu in #1817

Improve docstrings for reverse and reverse! by @sogaiu in #1818

Improve docstrings of every? and any? by @sogaiu in #1819

Improve docstrings for all, some, and count by @sogaiu in #1820

Improve docstrings for keep, map, and mapcat by @sogaiu in #1821

Improve docstrings for sum and friends by @sogaiu in #1824

Improve docstring for interleave by @sogaiu in #1825

Improve docstring for describe by @sogaiu in #1826

Improve docstring for update by @sogaiu in #1827

Improve docstring for loop by @sogaiu in #1830

Improve docstring for last by @sogaiu in #1829

Improve docstring for length by @sogaiu in #1828