Improvements in locale:translate_search fixes

[gavishpoddar]

This PR fixes #930

Adds support for last decade, next decade, etc in search_dates

PL suggest if any change is required.

Thanks

[codecov]

Codecov Report

Merging #953 (ecbfc2b) into master (ad50964) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #953   +/-   ##
=======================================
  Coverage   98.26%   98.27%           
=======================================
  Files         231      231           
  Lines        2597     2609   +12     
=======================================
+ Hits         2552     2564   +12     
  Misses         45       45           

Impacted Files	Coverage Δ
dateparser/languages/locale.py	98.69% <100.00%> (+0.04%)	⬆️

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[noviluni]

Nice job!
All tests are passing, so it seems that it works pretty good without breaking anything 💪

We can merge it when addressing the suggestions! :)

[gavishpoddar]

Thanks, @noviluni, for the quick review, I have made the changes you suggested.