`alg` is not a keyword argument

[araujoms]

When the argument alg was added to eigen and eigvals in JuliaLang/julia#49355 it was added as a positional argument, but the docstrings and error messages refer to it as a keyword argument. One could simply change them, but since svd has accepted an actual keyword argument alg since Julia 1.3, perhaps it is better to make the new one a keyword argument for consistency? That wouldn't break anything since Julia 1.12 is not yet released.

[jishnub]

This was the idea behind JuliaLang/julia#55481, although it didn't get merged in time. Perhaps I should resurrect it.

[araujoms]

Please do, I think that would be the optimal solution.