🌐 Add French translation for docs/tutorial/body.md

[Smlep]

Hey everyone! 👋

Here is the PR to translate the body page of the tutorial documentation into french.
See the french translation tracking issue here.

Thanks for the reviews👌

[codecov]

Codecov Report

Merging #3671 (835b92a) into master (68c43eb) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master     #3671   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          410       410           
  Lines        10281     10281           
=========================================
  Hits         10281     10281           

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[github-actions]

📝 Docs preview for commit fd665a2 at: https://61110e2afdc6d3d353d41047--fastapi.netlify.app

[tiangolo]

Awesome, thank you @Smlep! ☕ 🥐

And thanks for the reviews @RuellePaul and @rjNemo 🙇