Support Julia 1.12

[eschnett]

Closes #64

[codecov]

Codecov Report

❌ Patch coverage is 65.11628% with 15 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.94%. Comparing base (7c34681) to head (846a6c7).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/MappedArrays.jl	65.11%	15 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #65      +/-   ##
==========================================
- Coverage   85.60%   78.94%   -6.66%     
==========================================
  Files           1        1              
  Lines         132      152      +20     
==========================================
+ Hits          113      120       +7     
- Misses         19       32      +13     

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[eschnett]

I do not think there is a good way to get nice output for closures with Julia 1.12. The closures themselves are more complex, they contains type checks etc., and reconstituting x -> x*x would now be a major effort. If we wanted this then we should probably use an external package for this, or maybe modify Julia itself to keep a pretty-printable syntax tree around.

@timholy CI should now be working – can you approve running the CI workflow?

[eschnett]

Ping – can you approve the CI workflow?

[eschnett]

Ping

[eschnett]

Can you run the CI?

[timholy]

Sorry for the delay; to any other JuliaLinearAlgebra folks, feel free to merge this once a decision has been made on the naming of the anonymous function in the test. (I'm OK with whatever.)

[timholy]

var\"#21#22\" seems like it could be fragile in a test; what if we modify the package so it creates additional gensyms?

Likewise below