Ignore /build even if it’s a symlink, but only at top-level.
Remove deprecated owned vector from iterator example.
auto merge of #14546 : SimonSapin/rust/patch-13, r=alexcrichton

CC @alexcrichton
Closes #14545
Register new snapshots
std: Rename {Eq,Ord} to Partial{Eq,Ord}

This is part of the ongoing renaming of the equality traits. See #12517 for more
details. All code using Eq/Ord will temporarily need to move to Partial{Eq,Ord}
or the Total{Eq,Ord} traits. The Total traits will soon be renamed to {Eq,Ord}.

cc #12517

[breaking-change]
auto merge of #14547 : reem/rust/remove-owned-vec-docs, r=alexcrichton

The last example in the containers and iterators guide had a superfluous owned vector in it. Everything works fine without it, so I removed it to avoid confusion.
syntax: Prepare for Total{Eq,Ord} => {Eq,Ord}

This commit adds the groundwork for the renaming of the Total{Eq,Ord} traits.
After this commit hits a snapshot, the traits can be renamed.
auto merge of #14534 : alexcrichton/rust/snapshots, r=sfackler

This is part 2 of the saga of renaming the Partial/Total equality and comparison traits.
rustc: Update how Gc<T> is recognized

This commit uses the same trick as ~/Box to map Gc<T> to @T internally inside
the compiler. This moves a number of implementations of traits to the `gc`
module in the standard library.

This removes functions such as `Gc::new`, `Gc::borrow`, and `Gc::ptr_eq` in
favor of the more modern equivalents, `box(GC)`, `Deref`, and pointer equality.

The Gc pointer itself should be much more useful now, and subsequent commits
will move the compiler away from @T towards Gc<T>

[breaking-change]
syntax: Move the AST from @T to Gc<T>
rustc: Move the AST from @T to Gc<T>