Display attributes with correct capitalization

[CaroFG]

Description

Attributes are uppercased. It's prettier but it can be confusing. Recently, a free-trial customer was getting 0 search results, because he had copied the searchable attributes from the mini-dashboard.

As @guimachiavelli pointed out:

You could argue meilisearch/documentation#2 is not super necessary, but it still seems like an easy enough thing to do and might serve as a subtle way of signalling capitalization is important.

Expected behavior

Attributes should be shown as they were sent, with the original case.

Current behavior

They are uppercased.

Screenshots or Logs
If applicable, add screenshots or logs to help explain your problem.

Environment (please complete the following information):

• Meilisearch version: [e.g. v.0.24.0]
• Browser: [e.g. Chrome version 90.0]

[curquiza]

Thanks
I put this issue as good first issue for the community. Feel free to open a PR