Extend the interior function to MultiRegionFields

[siddharthabishnu]

Consider the following MWE:

julia> using Oceananigans
┌ Warning: You are using Julia v1.11 or later!"
│ Oceananigans is currently tested on Julia v1.10."
│ If you find issues with Julia v1.11 or later,"
│ please report at https://github.com/CliMA/Oceananigans.jl/issues/new
└ @ Oceananigans ~/Library/CloudStorage/Dropbox/StudyFolder/PostDocMITDesktop/Codes/Oceananigans/main/src/Oceananigans.jl:124
[ Info: Oceananigans will use 8 threads

julia> arch = CPU()
CPU()

julia> Nx, Ny, Nz = 4, 4, 4
(4, 4, 4)

julia> grid = ConformalCubedSphereGrid(arch; panel_size=(Nx, Ny, Nz), z=(-1, 0), horizontal_direction_halo=2, radius=1)
ConformalCubedSphereGrid{Float64, Oceananigans.Grids.FullyConnected, Oceananigans.Grids.FullyConnected, Bounded} partitioned on CPU():
├── grids: 4×4×4 OrthogonalSphericalShellGrid{Float64, Oceananigans.Grids.FullyConnected, Oceananigans.Grids.FullyConnected, Bounded} on CPU with 2×2×2 halo and with precomputed metrics
├── partitioning: CubedSpherePartition with (1 region in each panel)
├── connectivity: CubedSphereConnectivity
└── devices: (CPU(), CPU(), CPU(), CPU(), CPU(), CPU())

julia> c = CenterField(grid)
CubedSphereField{Center, Center, Center}
├── grid: 4×4×4 ConformalCubedSphereGrid{Float64, Oceananigans.Grids.FullyConnected, Oceananigans.Grids.FullyConnected, Bounded} on CPU with 2×2×2 halo
├── boundary conditions: FieldBoundaryConditions
└── data: MultiRegionObject{NTuple{6, OffsetArrays.OffsetArray{Float64, 3, Array{Float64, 3}}}, NTuple{6, CPU}, KernelAbstractions.CPU}
    └── max=0.0, min=0.0, mean=0.0

julia> set!(c, 1)

Before this PR:

julia> interior(c)
ERROR: MethodError: no method matching interior(::MultiRegionObject{…}, ::Tuple{…}, ::ConformalCubedSphereGrid{…}, ::MultiRegionObject{…})
The function `interior` exists, but no method is defined for this combination of argument types.

Closest candidates are:
  interior(::FieldTimeSeries, ::Any...)
   @ Oceananigans ~/Library/CloudStorage/Dropbox/StudyFolder/PostDocMITDesktop/Codes/Oceananigans/main/src/OutputReaders/field_time_series.jl:720
  interior(::Field, ::Any...)
   @ Oceananigans ~/Library/CloudStorage/Dropbox/StudyFolder/PostDocMITDesktop/Codes/Oceananigans/main/src/Fields/field.jl:424
  interior(::OffsetArrays.OffsetArray, ::Any, ::Any, ::Any)
   @ Oceananigans ~/Library/CloudStorage/Dropbox/StudyFolder/PostDocMITDesktop/Codes/Oceananigans/main/src/Fields/field.jl:423
  ...

Stacktrace:
 [1] interior(f::Field{Center, Center, Center, Nothing, ConformalCubedSphereGrid{…}, MultiRegionObject{…}, MultiRegionObject{…}, Any, MultiRegionObject{…}, Nothing, MultiRegionObject{…}})
   @ Oceananigans.Fields ~/Library/CloudStorage/Dropbox/StudyFolder/PostDocMITDesktop/Codes/Oceananigans/main/src/Fields/field.jl:422
 [2] top-level scope
   @ REPL[8]:1
Some type information was truncated. Use `show(err)` to see complete types.

After this PR,

julia> interior(c)
MultiRegionObject{NTuple{6, SubArray{Float64, 3, Array{Float64, 3}, Tuple{UnitRange{Int64}, UnitRange{Int64}, UnitRange{Int64}}, false}}, NTuple{6, CPU}, KernelAbstractions.CPU}(([1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0;;; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0;;; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0;;; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0], [1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0;;; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0;;; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0;;; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0], [1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0;;; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0;;; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0;;; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0], [1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0;;; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0;;; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0;;; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0], [1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0;;; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0;;; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0;;; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0], [1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0;;; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0;;; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0;;; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0; 1.0 1.0 1.0 1.0]), (CPU(), CPU(), CPU(), CPU(), CPU(), CPU()), KernelAbstractions.CPU(false))

[tomchor]

I think this PR introduced the following error when building the docs:

Seen in #4687

[simone-silvestri]

I don't think is this one. The show method is not touched here. However, we should correct this issue