docs, tests, fix: fit fibonacci_fast to contributing guidelines

[setbit123]

Description of Change

Modify the fibonacci_fast.cpp to fit the project style requirements.
Solve a small part of issue #2456

Checklist

• Added description of change
• Added file name matches File name guidelines
• Added tests and example, test must pass
• Added documentation so that the program is self-explanatory and educational - Doxygen guidelines
• PR title follows semantic commit guidelines
• Search previous suggestions before making a new one, as yours may be a duplicate.
• I acknowledge that all my contributions will be made under the project's license.

Notes:

[setbit123]

cc @Panquesito7 @realstealthninja

[realstealthninja]

Thank you for your contribution!

[setbit123]

Thank you very much for providing valuable suggestions. I have made an attempt to revise my PR according to your advice.

cc @realstealthninja

[realstealthninja]

Very nicely done!

[setbit123]

Thank you for your response! I noticed the following errors in Compile checks (windows-latest):
error C2039: 'to_string': is not a member of 'std'
error C3861: 'to_string': identifier not found
error C2512: 'std::invalid_argument': no appropriate default constructor available
I tried adding some header files to solve this issue. Looking forward to your reply!

cc @realstealthninja

[setbit123]

It seems there is a new code style check that wasn’t present before. I made the necessary modifications.

cc @realstealthninja

[setbit123]

According to the check results, it seems there is still an issue with token permissions. I'm not sure if I have resolved this issue.

cc @realstealthninja