Update french translation / modification def dayssince in duration.py

[Anoerak]

Update of the french translation (corrections and adds) + modification of the
'def dayssince(value, today=None)' by replacing the value of line 118 with a variable in line 110 which will make the tranlsation easier for the future.

[Anoerak]

I think I know why the def dayssince test failed.
Since I changed the def and replace the return with a variable build as
days_ago = _(" ") + str(delta.days) + _(" days ago")
in order to ease the translation (in french, we would replace the " " by "il y a " and the " days ago" by " jours"), I needed to modify the expected results of the test from "x days ago" to " x days ago".
Should I close this PR and submit a new one with the corrected test?

[cdubz]

@Anoerak I think the approach we should take here instead is to bring the str(delta_days) in to the translatable string -- then you'll be able to put whatever you want before it without the filler space.

E.g. _("%(days_ago)s days ago") % {"days_ago": str(delta.days)}

[Anoerak]

Ok.
I'll look into that this weekend.

[cdubz]

@Anoerak 👋 Still looking to contribute to this branch?

[Anoerak]

Hi @cdubz ,
Sorry, things have been busy here :)
I've to meet some deadlines on a current project and will jump back on this branch right after if that's OK with you.

[cdubz]

Yep that’s fine. No worries!

[coveralls]

coverage: 98.94% (-0.04%) from 98.976% when pulling 9f33296 on Anoerak:master into 0c15868 on babybuddy:master.

[cdubz]

Thanks for you work here, @Anoerak! I only took this over because of the related #718 change.