docs: Update contributing file

[PKief]

Description

• Update table of contents
• Use only markdown syntax for the headlines
• Add samples for the folder wildcards
• Add extension recommendations for editing markdown files
• Add settings for formatting markdown files with the markdown lint extension per default

Contribution Guidelines

• By creating this pull request, I acknowledge that I have read the Contribution Guidelines for this project
• I have read the Code Of Conduct and promise to abide by these rules

[okineadev]

It's cool, I think then you can merge PR in which a script is added to the package.json for linting markdown

[github-actions]

Merge Successful

Thanks for your contribution! 🎉

The changes will be part of the upcoming update on the Marketplace.