DSPManager : Updated French Translations

(Patch Set 5)

- Better visibility.
- General optimization.
- Fixed misspelling French.

- Added several missing translations.
- Added "\u00A0" before and after hyphen.

- Adapatation compared to the original file.
- Header updated and standardized.
- Other small fixes.

Signed-off-by: Thibault LEMOINE <thibaultblizz@gmail.com>