linux/gnu*: add French translation

[open-source-learner]

Checklist

• The page(s) are in the correct platform directories: common, linux, osx, windows, sunos, android, etc.
• The page description(s) have links to documentation or a homepage.
• The page(s) follow the content guidelines.
• The page(s) follow the style guide.
• The PR contains at most 5 new pages.
• The PR is authored by me, or has been human-reviewed if it was created with AI or machine translation software.
• The PR title conforms to the recommended templates.
• Version of the command being documented (if known):
• Reference issue: Page translation request: outdated or missing French pages #13570
• Closes: #

Additional details:

[tldr-bot]

Hello! I've noticed something unusual when checking this PR at commit
c32b4477754130e4926604658aca6449622298e6:

• The page pages.fr/linux/gnuls.md seems to be a copy of pages.fr/linux/dir.md (54% matching).
• The page pages.fr/linux/gnumkdir.md seems to be a copy of pages.fr/common/lzgrep.md (50% matching).

Is this intended? If so, just ignore this comment. Otherwise, please double-check the commits.