reverse for sparse vector/matrix

[jishnub]

This ensures that reverse doesn't add spurious zeros to a sparse array. Currently, it's only implemented for vectors Implemented for both vectors and matrices.
On main

julia> S = sparsevec([2, 4, 5 ,8], [0.1, 0.2, 0.3, 0.4], 10)
10-element SparseVector{Float64, Int64} with 4 stored entries:
  [2]  =  0.1
  [4]  =  0.2
  [5]  =  0.3
  [8]  =  0.4

julia> reverse(S)
10-element SparseVector{Float64, Int64} with 8 stored entries:
  [2]  =  0.0
  [3]  =  0.4
  [4]  =  0.0
  [5]  =  0.0
  [6]  =  0.3
  [7]  =  0.2
  [8]  =  0.0
  [9]  =  0.1

julia> @btime reverse($S);
  315.448 ns (4 allocations: 352 bytes)

This PR

julia> reverse(S)
10-element SparseVector{Float64, Int64} with 4 stored entries:
  [3]  =  0.4
  [6]  =  0.3
  [7]  =  0.2
  [9]  =  0.1

julia> @btime reverse($S);
  113.827 ns (2 allocations: 192 bytes)

[codecov]

Codecov Report

Merging #450 (cac8c40) into main (e86b148) will increase coverage by 0.11%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #450      +/-   ##
==========================================
+ Coverage   85.40%   85.51%   +0.11%     
==========================================
  Files          13       13              
  Lines        8734     8803      +69     
==========================================
+ Hits         7459     7528      +69     
  Misses       1275     1275              

Files	Coverage Δ
src/SparseArrays.jl	83.33% <ø> (ø)
src/sparsematrix.jl	95.78% <100.00%> (+0.09%)	⬆️
src/sparsevector.jl	95.48% <100.00%> (+0.05%)	⬆️

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[jishnub]

Fixes JuliaLang/julia#51420

julia> A = sprand(5,5,0.3)
5×5 SparseMatrixCSC{Float64, Int64} with 8 stored entries:
  ⋅        0.860008   ⋅    ⋅         ⋅ 
  ⋅         ⋅         ⋅   0.569948   ⋅ 
 0.604659  0.428      ⋅   0.139034  0.205955
 0.673227   ⋅         ⋅    ⋅         ⋅ 
  ⋅         ⋅         ⋅   0.367848   ⋅ 

julia> reverse(A)
5×5 SparseMatrixCSC{Float64, Int64} with 8 stored entries:
  ⋅        0.367848   ⋅    ⋅         ⋅ 
  ⋅         ⋅         ⋅    ⋅        0.673227
 0.205955  0.139034   ⋅   0.428     0.604659
  ⋅        0.569948   ⋅    ⋅         ⋅ 
  ⋅         ⋅         ⋅   0.860008   ⋅