Can we make `blockcolrange` and `blockrowrange` public?

[gdalle]

These two functions are used in FiniteDiff.jl and possibly soon in SparseMatrixColorings.jl, but they are not part of the public API.

[gdalle]

Nevermind I see now that BlockArrays.blockcolsupport and BlockArrays.blockrowsupport are part of BlockArrays