Make data reflect a case where dev deps are existent.
base-db::CrateGraph::extend now adds dev dependencies for a crate
in case of its upgrading from a CrateOrigin::Lib kind of a crate to a
CrateOrigin::Local one.
Partially fixes#15656 . When a crate graph is extended which is the case when new workspaces are added to the project
the rules for deduplication were too strict. One problem that arises from this is that in certain conditions
when we see the same crate having different `CrateOrigin`s the first form would be maintained. This approach however
results in some unwanted results such as making renaming forbidden as this has been recently only made available for
local crates. The given example in #15656 can still not be resolved with this PR as that involves taking inconsistencies
between dependencies into consideration. This will be addressed in a future PR.
Detect sysroot dependencies using symlink copy
cc #7637
It is currently in a proof of concept stage, and it doesn't generates a copy. You need to provide your own sysroot copy in `/tmp/ra-sysroot-hack` in a way that `/tmp/ra-sysroot-hack/library/std/lib.rs` exists and `/tmp/ra-sysroot-hack/Cargo.toml` is [the one from this comment](https://github.com/rust-lang/rust-analyzer/issues/7637#issuecomment-1495008329). I will add the symlink code if we decide that this approach is not a dead end.
It seems to somehow work on my system. Go to definition into std dependencies works, type checking can look through fields if I make them public and `cfg_if` appears to work (I tested it by hovering both sides and seeing that the correct one is enabled). Though finding layout of `HashMap` didn't work.
Please try it and let me know if I should go forward in this direction or not.
