Rollup merge of rust-lang#66171 - JohnTitor:update-link, r=ehuss

Update link on CONTRIBUTING.md

This is a lost article of rust-lang#66162
Follow-up for rust-lang/rustc-dev-guide#491

CC: @mark-i-m

CONTRIBUTING.md

@@ -105,7 +105,7 @@ contributions to the compiler and the standard library. It also lists some
 really useful commands to the build system (`./x.py`), which could save you a
 lot of time.
 
-[rustcguidebuild]: https://rust-lang.github.io/rustc-guide/how-to-build-and-run.html
+[rustcguidebuild]: https://rust-lang.github.io/rustc-guide/building/how-to-build-and-run.html
 
 ## Pull Requests
 [pull-requests]: #pull-requests

src/librustc/infer/region_constraints/README.md

@@ -1,3 +1,3 @@
 For info on how the current borrowck works, see the [rustc guide].
 
-[rustc guide]: https://rust-lang.github.io/rustc-guide/mir/borrowck.html
+[rustc guide]: https://rust-lang.github.io/rustc-guide/borrow_check.html