Add `floatmin` and `floatmax`

[dlfivefifty]

[codecov-commenter]

Codecov Report

Merging #477 (055d231) into master (a3dc27f) will decrease coverage by 0.10%. The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #477      +/-   ##
==========================================
- Coverage   91.55%   91.44%   -0.11%     
==========================================
  Files          25       25              
  Lines        1752     1754       +2     
==========================================
  Hits         1604     1604              
- Misses        148      150       +2     

Impacted Files	Coverage Δ
src/IntervalArithmetic.jl	100.00% <ø> (ø)
src/intervals/arithmetic.jl	96.42% <0.00%> (-0.78%)	:arrow_down:

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[dpsanders]

What's the use case for this?

[dpsanders]

Currently there's

julia> @interval(Inf)
[1.79769e+308, ∞]

(Note that in general we now prefer using interval(a, b) instead of @interval(a, b) since the former is much faster. However, infinity is a special case.

[dlfivefifty]

I use it in the convergence check in the adaptive QR implemented in InfiniteLinearAlgebra.jl

[lucaferranti]

julia> @interval(Inf)
[1.79769e+308, ∞]

that's not the case anymore on master, it has been changed in #461