Add interface support for LinearAlgebra.Diagonal

[lkdvos]

This PR extends the sparse interface functions for LinearAlgebra.Diagonal, along with some basic tests.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 10 lines in your changes missing coverage. Please review.

Project coverage is 63.13%. Comparing base (aceca8c) to head (b6ccf93).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/wrappers.jl	0.00%	10 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #16      +/-   ##
==========================================
- Coverage   65.53%   63.13%   -2.40%     
==========================================
  Files           6        6              
  Lines         264      274      +10     
==========================================
  Hits          173      173              
- Misses         91      101      +10     

Flag	Coverage Δ
docs	63.00% <0.00%> (-2.40%)	⬇️

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[mtfishman]

Great, thanks!

[lkdvos]

(I still can't merge this)

[mtfishman]

(I still can't merge this)

Ah, that's annoying, we'll have to look into giving you merge rights. I'll merge in the meantime.