Filter doctests instead of preloading packages

[andreasnoack]

If a sparse matrix isn't in the local MatrixDepot cache then the matrixdepot function outputs some extra lines related to the download that causes doctests failure. To work around that, I've added a line that downloads the matrix as a part of the docs setup, see

TSVD.jl/docs/make.jl

Line 6 in 2d8f0d4

:(using TSVD, MatrixDepot; matrixdepot("LPnetlib/lp_osa_30"));

and

TSVD.jl/.github/workflows/CI.yml

Line 67 in 2d8f0d4

:(using TSVD, MatrixDepot; matrixdepot("LPnetlib/lp_osa_30"));

. It would be better to use the filtering functionality in Documenter to filter this out. However, it requires that I figure out how to write the regex.