docs: update related packages sections

[stdlib-bot]

This PR

• updates the related packages section of READMEs to include links to related packages.

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
number/int64/ctor	$\\color{red}603/685$ $\\color{green}+88.03\\%$	$\\color{red}51/55$ $\\color{green}+92.73\\%$	$\\color{red}9/11$ $\\color{green}+81.82\\%$	$\\color{red}603/685$ $\\color{green}+88.03\\%$

The above coverage report was generated for the changes in this PR.