fix ambiguities

[putianyi889]

Aqua is set to check ambiguities.

• Fixes Is there a reason to skip ambiguity test in Aqua? #36

Related changes:

• Some tests change from NotANumber to ArgumentError NotANumber vs ArgumentError #38
• Standalone +∞ now refers to RealInfinity(). Some +/- test results have changed accordingly, although not consistent. Infinity vs RealInfinity() #39
• Support (fld|cld|div)(∞, x) where x<0
• Aqua tests are moved to the end of tests to make sure things work before fixing ambiguities.
• Support infinite Complex{float} + ∞
• min|max are set to follow Julia base convention, that is, min(x,y)=x and max(x,y)=y if x==y. This impacts ℵ₀ and ∞ specifically. Comparing ℵ₀ and ∞ #41
• Fixes Inconsistency in arithmetic of infinites of different types #47

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.96%. Comparing base (1b8c2ce) to head (fee60c4).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #40      +/-   ##
==========================================
- Coverage   98.39%   97.96%   -0.43%     
==========================================
  Files           2        6       +4     
  Lines         373      197     -176     
==========================================
- Hits          367      193     -174     
+ Misses          6        4       -2     

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[putianyi889]

A crucial line somehow loses coverage. Removing the line results in failed tests. I've added a note to the line.

[putianyi889]

Related: JuliaApproximation/ClassicalOrthogonalPolynomials.jl#154