Tidy French translation file

[tgreenx]

Purpose

This PR fixes a failing unit test by running make POFILES=fr.po tidy-po on the French translation file.

Context

Follow-up to #422

Changes

• Tidy fr.po

How to test this PR

Unit tests should now pass, in particular t/po-files.t:

$ prove t/po-files.t
t/po-files.t .. 1/?     # Using msgcat version: msgcat (GNU gettext-tools) 0.21
t/po-files.t .. ok
All tests successful.
Files=1, Tests=3,  0 wallclock secs ( 0.01 usr  0.00 sys +  0.09 cusr  0.00 csys =  0.10 CPU)
Result: PASS