improve fr support

[noviluni]

Includes additions from the next PRs:

• Update fr.yaml #327
• Added: Supporting "ans" for "year" (FR) #357
• Update fr.json #577
• Update fr.yaml #594

Most of them modify the json file instead of the yaml file, so we could close them after releasing this.

Also fixes: #354

[codecov]

Codecov Report

Merging #672 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #672   +/-   ##
=======================================
  Coverage   95.23%   95.23%           
=======================================
  Files         302      302           
  Lines        2558     2558           
=======================================
  Hits         2436     2436           
  Misses        122      122           

Impacted Files	Coverage Δ
dateparser/data/date_translation_data/en.py	100.00% <ø> (ø)
dateparser/data/date_translation_data/fr.py	100.00% <ø> (ø)

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