doc: add docstrings to the result anlysis methods for sparse matrix preparations (#984)

* doc: add DI.jl sparse preperation method docstrings

* Format with Runic

---------

Co-authored-by: Guillaume Dalle <22795598+gdalle@users.noreply.github.com>

Author: franckgaga

DifferentiationInterface/ext/DifferentiationInterfaceSparseMatrixColoringsExt/DifferentiationInterfaceSparseMatrixColoringsExt.jl

@@ -19,20 +19,81 @@ import SparseMatrixColorings as SMC
 
 abstract type SMCSparseJacobianPrep{SIG} <: DI.SparseJacobianPrep{SIG} end
 
+"""
+    SMC.sparsity_pattern(prep::DI.SparseJacobianPrep)
+
+Return the sparsity pattern of a sparse `prep` object created by [`prepare_jacobian`](@ref).
+"""
 SMC.sparsity_pattern(prep::DI.SparseJacobianPrep) = prep.sparsity
+
+"""
+    SMC.column_colors(prep::DI.SparseJacobianPrep)
+
+Return the column colors of a sparse `prep` object created by [`prepare_jacobian`](@ref).
+"""
 SMC.column_colors(prep::DI.SparseJacobianPrep) = column_colors(prep.coloring_result)
+
+"""
+    SMC.column_groups(prep::DI.SparseJacobianPrep)
+
+Return the column groups of a sparse `prep` object created by [`prepare_jacobian`](@ref).
+"""
 SMC.column_groups(prep::DI.SparseJacobianPrep) = column_groups(prep.coloring_result)
+
+"""
+    SMC.row_colors(prep::DI.SparseJacobianPrep)
+
+Return the row colors of a sparse `prep` object created by [`prepare_jacobian`](@ref).
+"""
 SMC.row_colors(prep::DI.SparseJacobianPrep) = row_colors(prep.coloring_result)
+
+"""
+    SMC.row_groups(prep::DI.SparseJacobianPrep)
+
+Return the row groups of a sparse `prep` object created by [`prepare_jacobian`](@ref).
+"""
 SMC.row_groups(prep::DI.SparseJacobianPrep) = row_groups(prep.coloring_result)
+
+"""
+    SMC.ncolors(prep::DI.SparseJacobianPrep)
+
+Return the number of colors of a sparse `prep` object created by [`prepare_jacobian`](@ref).
+"""
 SMC.ncolors(prep::DI.SparseJacobianPrep) = ncolors(prep.coloring_result)
 
+
+"""
+    SMC.sparsity_pattern(prep::DI.SparseHessianPrep)
+
+Return the sparsity pattern of a sparse `prep` object created by [`prepare_hessian`](@ref).
+"""
 SMC.sparsity_pattern(prep::DI.SparseHessianPrep) = prep.sparsity
+
+"""
+    SMC.column_colors(prep::DI.SparseHessianPrep)
+
+Return the column colors of a sparse `prep` object created by [`prepare_hessian`](@ref).
+"""
 SMC.column_colors(prep::DI.SparseHessianPrep) = column_colors(prep.coloring_result)
+
+"""
+    SMC.column_groups(prep::DI.SparseHessianPrep)
+
+Return the column groups of a sparse `prep` object created by [`prepare_hessian`](@ref).
+"""
 SMC.column_groups(prep::DI.SparseHessianPrep) = column_groups(prep.coloring_result)
+
+"""
+    SMC.ncolors(prep::DI.SparseHessianPrep)
+
+Return the number of colors of a sparse `prep` object created by [`prepare_hessian`](@ref).
+"""
 SMC.ncolors(prep::DI.SparseHessianPrep) = ncolors(prep.coloring_result)
 
+
 include("jacobian.jl")
 include("jacobian_mixed.jl")
 include("hessian.jl")
 
+
 end