Replace discovered unknown mods with their known versions once available

[XDelta]

I had harmony 2.3.3 in my rml_libs folder before it was on the manifest, now that it is on the manifest, the entry for harmony is still marked as unknown despite matching the hash of an entry on the manifest.

[Gawdl3y]

This is something that I assumed would be an issue at some point and had an entry on my todo list for, haha. It's because discovered "unknown" mods don't get automatically replaced by a known mod once one becomes available - yet.

[XDelta]

The unknown one here is on the manifest and could be matched by hash and name. (although hash is probably plenty)