Update src/mir/optimizations.md

Co-Authored-By: Who? Me?! <[email protected]>

Author: spastorino

src/mir/optimizations.md

@@ -8,8 +8,8 @@ to do, so compilation is faster. Note that since MIR is generic (not
 effective; we can optimize the generic version, so all of the monomorphizations
 are cheaper!
 
-[mir]: https://rustc-dev-guide.rust-lang.org/mir/index.html
-[monomorph]: https://rustc-dev-guide.rust-lang.org/appendix/glossary.html?highlight=monomorphize#appendix-c-glossary
+[mir]: ./index.md
+[monomorph]: ../appendix/glossary.md
 
 MIR optimizations run after borrow checking. We run a series of optimization
 passes over the MIR to improve it. Some passes are required to run on all code,