Add generic version of Sequence for any number type

[atifaziz]

This PR adds a generic version of Sequence as described in #892.

Under .NET 7, Sequence(int, int, int) defers to Sequence<T>(T, T, T) and is therefore tested for when T is int.

[codecov]

Codecov Report

Attention: Patch coverage is 94.44444% with 1 line in your changes missing coverage. Please review.

Project coverage is 93.22%. Comparing base (5dc9e18) to head (1ac5b79).
Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
MoreLinq/Sequence.cs	94.44%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #893      +/-   ##
==========================================
- Coverage   93.23%   93.22%   -0.01%     
==========================================
  Files         112      112              
  Lines        3400     3410      +10     
  Branches      962      962              
==========================================
+ Hits         3170     3179       +9     
- Misses        214      215       +1     
  Partials       16       16              

Flag	Coverage Δ
	93.22% <94.44%> (-0.01%)	⬇️

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[viceroypenguin]

Approved in principle. Will wait to give final approval.

[viceroypenguin]

This PR should wait until v4.0.0, along with .net7 release. Expectation is that v3.4.0 is existing changes plus nullability fixes to include at most .net6 (including conflicting behavior in certain methods). Future improvements should be delayed until after 3.4.0 is released.