benchmarks: custom click type for grid params

[mloubout]

Fixes issue with mulit-params with latest click and benchmark.

Superseeds #1831 and #1692

[codecov]

Codecov Report

Merging #1832 (676266a) into master (fa20c7c) will decrease coverage by 0.00%.
The diff coverage is 75.00%.

@@            Coverage Diff             @@
##           master    #1832      +/-   ##
==========================================
- Coverage   89.54%   89.53%   -0.01%     
==========================================
  Files         209      209              
  Lines       34479    34487       +8     
  Branches     5206     5209       +3     
==========================================
+ Hits        30873    30879       +6     
- Misses       3115     3116       +1     
- Partials      491      492       +1     

Impacted Files	Coverage Δ
benchmarks/user/benchmark.py	62.85% <75.00%> (+0.48%)	⬆️

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[FabioLuporini]

LGTM. Thanks.

[rhodrin]

Couple of typo's in the NTuple description:

A floating subtype of click's Tuple that allows inputs with fewer elements.
Instead of accepting only tuples of exact length, this accepts tuples
of length up to the definition size.

[mloubout]

Fixed typos