l10n: fr.po: hotfix for commit 6b388fc

Fix many typos and add some new translations (1277/2080 messages
translated).

Closes git-l10n/git-po/pull/63.

Signed-off-by: Sebastien Helleu <flashcode@flashtux.org>
Signed-off-by: Jiang Xin <worldhello.net@gmail.com>