Remove direct reference to Base.libblas_name and use const. Minor hygiene change, may not be worth a commit.
Fix invalid doc crossrefs: #8033

- Sets current module scope for manual/metaprogramming so that function cross-references work
- Fully qualify module scope for `gemm!` -> `Base.LinAlg.BLAS.gemm!`
Merge pull request #8035 from gchisholm/master

Remove direct reference to Base.libblas_name