Fix many things reported by JET

[lgoettgens]

Resolve #130.

• [n/a] The code is properly formatted and commented.
• [n/a] Substantial new functionality is documented within the docs.
• [n/a] All new functionality is tested.
• All of the automated tests on github pass.
• We recently started enforcing formatting checks. If formatting issues are reported in the new code you have written, please correct them.

I was able to bring the number of reports down to 33 on julia 1.10. On julia 1.11.0-rc3, there are only 19 left. Many of the remaining things are due to some iterator collection magic in julia base, where I at some point gave up trying to understand it.

What will certainly help with the JET report and type stability in general, but what I see out of scope of this small project:

• Use some type for time and restrict many of the type signatures for it to Union{Nothing, TimeType}. It really does not matter if one uses Float64 or DateTime or whatever for it, but this would help the compiler in some places.
• Resumable functions currently don't allow the compiler to do small union splitting. Consider the following function

function foo(x::Union{Nothing, Int})
  if isnothing(x)
    error("x is nothing")
  end
  # x gets inferred as Int
  ...
end

If we now tag this function as resumable, x will still be referred as Union{Nothing, Int} there. For the places that came up I circumvented this by introducing a new variable that just has type Int.

[codecov]

Codecov Report

Attention: Patch coverage is 70.58824% with 5 lines in your changes missing coverage. Please review.

Project coverage is 73.17%. Comparing base (4eeb57a) to head (a1e7672).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/states_registers_networks_getset.jl	0.00%	3 Missing ⚠️
src/backends/clifford/should_upstream.jl	0.00%	1 Missing ⚠️
src/baseops/traceout.jl	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #152      +/-   ##
==========================================
+ Coverage   73.03%   73.17%   +0.13%     
==========================================
  Files          41       41              
  Lines        1732     1737       +5     
==========================================
+ Hits         1265     1271       +6     
+ Misses        467      466       -1     

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[Krastanov]

Thank you so much! Please send me an email at [email protected] with your name and email and a link to the bounty, so I can set up your reimbursement process with NumFOCUS (it might take a few weeks as we do them in batches and they are still setting everything up for their first batch).