More generalizations for generic block types

[mtfishman]

Splitting off more generalizations from #136.

[codecov]

Codecov Report

Attention: Patch coverage is 88.88889% with 1 line in your changes missing coverage. Please review.

Project coverage is 75.29%. Comparing base (51fceec) to head (6c1b5e0).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/blocksparsearrayinterface/arraylayouts.jl	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #144      +/-   ##
==========================================
+ Coverage   75.26%   75.29%   +0.02%     
==========================================
  Files          35       35              
  Lines        1807     1809       +2     
==========================================
+ Hits         1360     1362       +2     
  Misses        447      447              

Flag	Coverage Δ
docs	7.75% <33.33%> (+0.10%)	⬆️

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