feat: add findIndex method to array/fixed-endian-factory

[pranav-1720]

Resolves #3142

Description

What is the purpose of this pull request?

• Adds findIndex method to array/fixed-endian-factory
• Add tests for the respective method
• Add benchmarks files for the respective method
• Updates README for fixed-endian-factory for the respective method

Related Issues

Does this pull request have any related issues?

This pull request:

• resolves #3142

Questions

Any questions for reviewers of this pull request?

No.

Other

Any other information relevant to this pull request? This may include screenshots, references, and/or implementation notes.

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
array/fixed-endian-factory	$\color{red}830/1089$ $\color{green}+76.22\%$	$\color{red}61/70$ $\color{green}+87.14\%$	$\color{red}13/24$ $\color{green}+54.17\%$	$\color{red}830/1089$ $\color{green}+76.22\%$

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

[pranav-1720]

HI, I do not have much experience with github so i was having trouble in editing the previous pull request for this issue. The changes i was making in my local machine were not getting pushed to my fork for some reason. I am not sure why it is showing commits from other users as well even though the changes to the file are limited to the findindex method of fixed-endian-factory.
Not sure what command to run to clean the git history. feedback on changes to be made or what git command to run to clean the histroy would be appreciated.

[adityacodes30]

maybe your branch history has diverged, if you dont have much exp with git your're better off just wiping the slate clean and reimplementing , the steps in contributing guidelines might help