Add deprecated ind2sub(::NTuple{N,Integer}, ::CartesianIndex{N}) (#23708)

Makes the return type change of #22907 less breaking by allowing the
common pattern `ind2sub(size(a), indmax(a))` to still work.

Author: martinholters

base/deprecated.jl

@@ -1822,6 +1822,10 @@ import .Iterators.enumerate
     return p
 end
 
+# ease transition for return type change of e.g. indmax due to PR #22907 when used in the
+# common pattern `ind2sub(size(a), indmax(a))`
+@deprecate(ind2sub(dims::NTuple{N,Integer}, idx::CartesianIndex{N}) where N, Tuple(idx))
+
 @deprecate contains(eq::Function, itr, x) any(y->eq(y,x), itr)
 
 # PR #23690