Find a better method for linking external documentation files
Currently un-algebra
modules use the nightly external_doc
feature to link to external documentation files (e.g. references and further reading). This means the crate--even as a 2018 edition crate--requires a nightly compiler version to build.
Research other approaches to documentation linking (e.g. a using documentation-only sub-modules) that would allow a stable edition compiler to build the crate.