atom, clear, convert, df: sync French translations with English pages

[nicokosi]

Fix a few fr warnings from https://lukwebsforge.github.io/tldri18n/.

• The PR title conforms to the recommended templates.
• The page follows the content guidelines.

[bl-ue]

This type of translation PR is one of my favorite! 🧡

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@nicokosi FYI—I just corrected the spaces before the colons to the French thin unbreakable ones. See #5152 for details.

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@nicokosi can you update your fork? It's a bit out-of-date. Here's how:

# switch to the master branch
git checkout master

# only do this step if you don't already the upstream remote (check with `git remote -v`)
git remote add upstream https://github.com/tldr-pages/tldr.git

# download the latest commits from the main repo into a temporary place
git fetch upstream master

# sync the latest commits into your fork's local master branch, in their correct order
git rebase upstream/master

# push everying up to your fork
git push

[bl-ue]

Also @nicokosi, will you please join our Gitter channel? You can just login using your GitHub account. I'd like to say something to you ;)