feat: include gists in top language data

### Is your feature request related to a problem? Please describe.

Yes, if a user makes a lot of gists then the data about what are their top languages becomes inaccurate.

For example on my friend's page there are some gists in Jupyter Notebook, C and so on:
https://gist.github.com/tomrockdsouza

However, these programming languages don't even show up in his top-langs:
https://github-readme-stats.vercel.app/api/top-langs/?username=tomrockdsouza&size_weight=0.5&count_weight=0.5&langs_count=10

### Describe the solution you'd like

It would be great if commits from gists were counted as well, they are basically git repos.

### Describe alternatives you've considered

_No response_

### Additional context

My man would finally have Python as his top language and not HTML if this were implemented.

Start at the top-langs API endpoint shown in the issue and trace how language data is gathered. Check GitHub's gist repositories and commits, then verify that languages from gists are included in the user's top-language results alongside repository data.

Written by the indexing model from the issue text.