Finish translation for Learn/index.fr.md
Merge pull request #421 from lefessan/learn-index.fr.md

Finish translation for Learn/index.fr.md
Use an UTF8 locale for news dates
Merge branch 'master' of github.com:ocaml/ocaml.org into docs-index.fr.md
Factorize “lang_of_filename” to Utils
Translate "Edit this page"
Make language links clickable on "Learn",...

This stems from the discussion
https://github.com/ocaml/ocaml.org/pull/422#issuecomment-36423284
Merge branch 'master' into docs-index.fr.md
Put back breadcrumbs