Fixes from Linkcheck

Author: simonsan

src/code-considerations/breaking-changes/fundamental.md

@@ -9,7 +9,7 @@ Type annotated with the `#[fundamental]` attribute have different coherence rule
 - `Box<T>`
 - `Pin<T>`
 
-Typically, the scope of [breakage in new trait impls](./reviewing-code/breakage/new-trait-impls.md) is limited to inference and deref-coercion. New trait impls on `#[fundamental]` types may overlap with downstream impls and cause other kinds of breakage.
+Typically, the scope of [breakage in new trait impls](./new-trait-impls.md) is limited to inference and deref-coercion. New trait impls on `#[fundamental]` types may overlap with downstream impls and cause other kinds of breakage.
 
 [RFC 1023]: https://rust-lang.github.io/rfcs/1023-rebalancing-coherence.html
 

src/code-considerations/breaking-changes/new-trait-impls.md

@@ -33,7 +33,7 @@ let b = Arc::from("a");
 
 will no longer compile, because we've previously been relying on inference to figure out the `T` in `Box<T>`.
 
-This kind of breakage can be ok, but a [crater] run should estimate the scope.
+This kind of breakage can be ok, but a [crater](../../tools-and-bots/crater.md) run should estimate the scope.
 
 ## Deref coercion breaks when a new impl is introduced