translation update
Merge pull request #63 from dokuwiki-translate/lang_update_138

Translation update (fr)
Remove longdesc.
The longdesc attribute should be a uri which points to more information about the image (http://www.w3.org/TR/html401/struct/objects.html#adef-longdesc-IMG), this now produces invalid html. Also it does not remove/replace things like double quotes from the description field messing up syntax.