remove eltype interface-piracy

[thchr]

These specializations are unnecessary since the eltype(Type{AbstractArray{T}}) where T fallback already ensures this behavior; i.e., the interface of the supertype already provides this.

Removing this was motivated by a discussion in the ttfx Slack channel where vtjnash indicated that these types of superfluous interface-extensions could be considered a form of piracy.

This addresses the following entry from a @snoopr report:

inserting eltype(::Type{SparseArrays.CHOLMOD.Dense{T}}) where T<:Union{Float64, ComplexF64} @ SparseArrays.CHOLMOD ~/dev/julia-master/share/julia/stdlib/v1.10/SparseArrays/src/solvers/cholmod.jl:983 invalidated:
   backedges: 1: superseding eltype(::Type{<:AbstractArray{E}}) where E @ Base abstractarray.jl:239 with MethodInstance for eltype(::Type{<:AbstractArray{T, N}} where {T, N}) (4 children)

[codecov-commenter]

Codecov Report

Merging #385 (07532b2) into main (5fc5771) will decrease coverage by 0.01%.
The diff coverage is n/a.

📣 This organization is not using Codecov’s GitHub App Integration. We recommend you install it so Codecov can continue to function properly for your repositories. Learn more

@@            Coverage Diff             @@
##             main     #385      +/-   ##
==========================================
- Coverage   93.86%   93.86%   -0.01%     
==========================================
  Files          12       12              
  Lines        7487     7484       -3     
==========================================
- Hits         7028     7025       -3     
  Misses        459      459              

Impacted Files	Coverage Δ
src/solvers/cholmod.jl	90.65% <ø> (-0.04%)	⬇️

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[thchr]

Test failures are the same as seen in #380, i.e., unrelated.

[rayegun]

Fine, I'm not aware of any reason to keep these if they're all subtypes of AbstractArray