implement AbstractVector inference for ConvergentsIterator

[vtjnash]

Fixes JuliaLang/julia#43101

[codecov]

Codecov Report

Merging #1204 (24cb8a9) into master (a35f2a5) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1204      +/-   ##
==========================================
- Coverage   87.93%   87.92%   -0.02%     
==========================================
  Files          76       76              
  Lines       28336    28335       -1     
==========================================
- Hits        24918    24913       -5     
- Misses       3418     3422       +4     

Impacted Files	Coverage Δ
src/gaussiannumbers/continued_fraction.jl	100.00% <100.00%> (ø)
src/Nemo.jl	27.11% <0.00%> (-1.70%)	⬇️
src/flint/fmpq.jl	93.76% <0.00%> (-0.30%)	⬇️

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[thofma]

Should be fixed by JuliaLang/julia#43106. Thanks @vtjnash for your help.