Various improvement to french translation

[Neluji]

Some french translations were not really representative of the actual command effect or field role. I also took the opportunity to correct some little mistakes.

Short description of what this resolves:

French translations issues

Changes proposed in this pull request:

• Semantic meaning fixes
• Grammatical fixes

How Has This Been Tested?

Not tested, as not relly needed

Checklist:

• [x] I have read the contribution guidelines.
• [ ] My change requires a change to the documentation and GitHub Wiki.
• [ ] I have updated the documentation and Wiki accordingly.