SciML documentation has broken links

Under the assumption that SciML website contains the current documentation, this has some broken links, e.g. on the main page, `interface` resolves to https://docs.sciml.ai/interface/, but probably should resolve to https://docs.sciml.ai/SymbolicUtils/stable/manual/interface/.

The links in the documentation on https://symbolicutils.juliasymbolics.org/ seem to work.