Fix best practices for .html and .py files in CONTRIBUTING.md
Fix best practices for .html and .py files in CONTRIBUTING.md

wisner23/serenata-de-amor,marcusrehm/serenata-de-amor,wisner23/serenata-de-amor,marcusrehm/serenata-de-amor,datasciencebr/serenata-de-amor,marcusrehm/serenata-de-amor,marcusrehm/serenata-de-amor,datasciencebr/serenata-de-amor