`finalize_coo!` does not check and add diagonal entries as claimed in the docstring

[mohamed82008]

The following implementation of finalize_coo! does nothing while the docstring says that this function should "Check and insert diagonal entries in COO vectors if needed." When is it "needed"? https://github.com/gridap/Gridap.jl/blob/28dd80b2ad2c099a85c030f4d6670552f8a2fdb5/src/Algebra/SparseMatrixCSC.jl#L23

[santiagobadia]

It is needed here, when we want to exploit symmetry

https://github.com/gridap/Gridap.jl/blob/28dd80b2ad2c099a85c030f4d6670552f8a2fdb5/src/Algebra/SymSparseMatrixCSR.jl#L33

[santiagobadia]

By the way, if you think that docstrings can be added/improved in the process, more than welcomed! I know that there are parts that are poorly documented.

[mohamed82008]

Sounds good. I will try to contribute my understanding to the docs.