vagrant, vagrant-plugin: add French translation

[aminelch]

• The page(s) are in the correct platform directories: common, linux, osx, windows, sunos, android, etc.
• The page(s) have at most 8 examples.
• 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 title conforms to the recommended templates.
• Version of the command being documented (if known):

[aminelch]

@noraj @nicokosi @Nico385412 can you check my changes

[noraj]

Also, while greffons (technically the best translation) and plugiciels (maybe only used in Quebec) are 100% correct, they may be less commonly used than modules or extensions. So you can choose to keep it or to adopt or more spread synonym, it's totally up to you.

[noraj]

For this check:

The page pages.fr/common/vagrant-plugin.md is outdated, based on the command contents itself, compared to the English page.

It's a false positive, it's actually the english page that contains an error: #15767.

[noraj]

LGTM now. Thank you for your work @aminelch.

[aminelch]

LGTM now. Thank you for your work @aminelch.

welcome