`patch` command should ignore `lib` subnamespace

[pchiusano]

A typical process is you update one of your dependencies, then want to apply the patch from its new release to your codebase. Like you'd type patch lib.something.shiny_new_version.patch at your project root.

That does not necessarily mean you want to apply that patch to all the stuff in lib. For that you could cd into lib.

[ceedubs]

I just noticed something related. If you run replace foo bar you end up with todo items within your lib namespace. This probably boils down to the same issue, but I thought that it would be worth explicitly calling out replace behavior for whomever works on this and writes test transcripts.