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
math/base/special/cotd	$\\color{green}176/176$ $\\color{green}+100.00\\%$	$\\color{green}5/5$ $\\color{green}+100.00\\%$	$\\color{green}2/2$ $\\color{green}+100.00\\%$	$\\color{green}176/176$ $\\color{green}+100.00\\%$
random/base/arcsine	$\\color{green}485/485$ $\\color{green}+100.00\\%$	$\\color{green}58/58$ $\\color{green}+100.00\\%$	$\\color{green}12/12$ $\\color{green}+100.00\\%$	$\\color{green}485/485$ $\\color{green}+100.00\\%$

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