Improve show for Qobj/QobjEvo tuples

[ytdHuang]

Checklist

Thank you for contributing to QuantumToolbox.jl! Please make sure you have finished the following tasks before opening the PR.

• Please read Contributing to QuantumToolbox.jl.
• Any code changes were done in a way that does not break public API.
• Appropriate tests were added and tested locally by running: make test.
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• (If necessary) the CHANGELOG.md should be updated (regarding to the code changes) and built by running: make changelog.

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Description

The current show for Qobj tuples print as the following style:

julia> a = destroy(2);
julia> (a, a', a + a')
(Quantum Object:   type=Operator   dims=[2]   size=(2, 2)   ishermitian=false
2×2 SparseMatrixCSC{ComplexF64, Int64} with 1 stored entry:
     ⋅      1.0+0.0im
     ⋅          ⋅    , Quantum Object:   type=Operator   dims=[2]   size=(2, 2)   ishermitian=false
2×2 Adjoint{ComplexF64, SparseMatrixCSC{ComplexF64, Int64}} with 1 stored entry:
     ⋅          ⋅    
 1.0-0.0im      ⋅    , Quantum Object:   type=Operator   dims=[2]   size=(2, 2)   ishermitian=true
2×2 SparseMatrixCSC{ComplexF64, Int64} with 2 stored entries:
     ⋅      1.0+0.0im
 1.0+0.0im      ⋅    )

julia> (a, QobjEvo(a))
(Quantum Object:   type=Operator   dims=[2]   size=(2, 2)   ishermitian=false
2×2 SparseMatrixCSC{ComplexF64, Int64} with 1 stored entry:
     ⋅      1.0+0.0im
     ⋅          ⋅    , Quantum Object Evo.:   type=Operator   dims=[2]   size=(2, 2)   ishermitian=false   isconstant=true
MatrixOperator(2 × 2))

With this PR, it will print like (every Qobj / QobjEvo starts from a new line):

julia> (a, a', a + a')
(Quantum Object:   type=Operator   dims=[2]   size=(2, 2)   ishermitian=false
2×2 SparseMatrixCSC{ComplexF64, Int64} with 1 stored entry:
     ⋅      1.0+0.0im
     ⋅          ⋅    ,
Quantum Object:   type=Operator   dims=[2]   size=(2, 2)   ishermitian=false
2×2 Adjoint{ComplexF64, SparseMatrixCSC{ComplexF64, Int64}} with 1 stored entry:
     ⋅          ⋅    
 1.0-0.0im      ⋅    ,
Quantum Object:   type=Operator   dims=[2]   size=(2, 2)   ishermitian=true
2×2 SparseMatrixCSC{ComplexF64, Int64} with 2 stored entries:
     ⋅      1.0+0.0im
 1.0+0.0im      ⋅    )

julia> (a, QobjEvo(a))
(Quantum Object:   type=Operator   dims=[2]   size=(2, 2)   ishermitian=false
2×2 SparseMatrixCSC{ComplexF64, Int64} with 1 stored entry:
     ⋅      1.0+0.0im
     ⋅          ⋅    ,
Quantum Object Evo.:   type=Operator   dims=[2]   size=(2, 2)   ishermitian=false   isconstant=true
MatrixOperator(2 × 2))

This is useful when checking the c_ops, e_ops, and so on, when they are in Tuple type.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.15%. Comparing base (1b48458) to head (f2bbd83).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #364      +/-   ##
==========================================
+ Coverage   93.14%   93.15%   +0.01%     
==========================================
  Files          41       41              
  Lines        2684     2688       +4     
==========================================
+ Hits         2500     2504       +4     
  Misses        184      184              

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