Updated fr.po (and audacity.iss) -- French submitted by Olivier Humbert...

... "#trebmuh" comment lines remain, where the translator may wish to review
and revise later.

Olivier's commit comments:

- disambiguation: decay (EN) -> déclin (FR)
- disambiguation : save (EN) -> sauvegarder (FR) and record (EN) -> enregistrer (FR)
- consistency around preset (EN) -> préréglage (FR)
- fixes "sample rate" which was translated with "fréquence d'échantillonnage" while the correct translation is "taux d'échantillonnage"
- fixes "bit rate" which was translated with "débit" while the correct translation is "débit binaire"
- fixes a misleading translation where a "bit  rate" (EN) was translated to "taux d'échantillonnage" instead of "débit binaire"

+ one string was half-translated
+ 5 typos
+ 1 frenglish
+ 1 better translation
+ 3 comments-to-self
+ updated timestamp
+ 1 missing translation

adds Christian Brochec in the header

+ a bunch of note-to-self precisions
+ a couple of better accelerators
+ typos
+ update the timestamp in the header
+ get the rid off the (useless now) "#| msgid" (which were ancient translation)

win/audacity.iss

@@ -338,7 +338,7 @@ es.ResetPrefs=¿Desea restablecer las preferencias?
 eu.ResetPrefs=Berrezarri Hobespenak?
 fa.ResetPrefs=Reset Preferences
 fi.ResetPrefs=Reset Preferences
-fr.ResetPrefs=Réinitialiser les  Préférences ?
+fr.ResetPrefs=Réinitialiser les préférences ?
 ga.ResetPrefs=Reset Preferences
 gl.ResetPrefs=Restabelecer as preferencias?
 he.ResetPrefs=?אתה רוצה לשחזר העדפות