fix: update geometric median documentation

[thedeeppp]

Resolves #5899 .

Description

What is the purpose of this pull request?

This pull request:

• Update return value comment to match implementation (returns 0)
• Remove unused math.h header from examples

Related Issues

Does this pull request have any related issues?

This pull request:

• resolves Address commit comments (commit afc07e7) #5899

Questions

Any questions for reviewers of this pull request?

No.

Other

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No.

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the contributing guidelines.

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@stdlib-js/reviewers

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
stats/base/dists/geometric/median	$\color{green}167/167$ $\color{green}+100.00\%$	$\color{green}9/9$ $\color{green}+100.00\%$	$\color{green}2/2$ $\color{green}+100.00\%$	$\color{green}167/167$ $\color{green}+100.00\%$
stats/base/dists/levy/median	$\color{green}182/182$ $\color{green}+100.00\%$	$\color{green}9/9$ $\color{green}+100.00\%$	$\color{green}2/2$ $\color{green}+100.00\%$	$\color{green}182/182$ $\color{green}+100.00\%$
stats/base/dists/triangular/logcdf	$\color{green}356/356$ $\color{green}+100.00\%$	$\color{green}36/36$ $\color{green}+100.00\%$	$\color{green}4/4$ $\color{green}+100.00\%$	$\color{green}356/356$ $\color{green}+100.00\%$

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

[kgryte]

@thedeeppp It looks like you've combined multiple sets of changes in this PR beyond what is necessary to satisfy #5899. I suggest either updating this PR to remove the additional changes or closing and creating new PR(s).

[thedeeppp]

@kgryte I will add a new PR soon