Prefer relative links

Signed-off-by: Yuki Okushi <jtitor@2k36.org>

Author: JohnTitor

src/building/how-to-build-and-run.md

@@ -63,7 +63,7 @@ If you set `download-ci-llvm = true`, in some circumstances, such as when
 updating the version of LLVM used by `rustc`, you may want to temporarily
 disable this feature. See the ["Updating LLVM" section] for more.
 
-["Updating LLVM" section]: /backend/updating-llvm.md#feature-updates
+["Updating LLVM" section]: ../backend/updating-llvm.md#feature-updates
 
 If you have already built `rustc` and you change settings related to LLVM, then you may have to
 execute `rm -rf build` for subsequent configuration changes to take effect. Note that `./x.py
@@ -254,7 +254,7 @@ For examples of the complete configuration necessary to build a target, please v
 select any target under the "Platform Support" heading on the left,
 and see the section related to building a compiler for that target.
 For targets without a corresponding page in the rustc book,
-it may be useful to [inspect the Dockerfiles](/tests/docker.md)
+it may be useful to [inspect the Dockerfiles](../tests/docker.md)
 that the Rust infrastructure itself uses to set up and configure cross-compilation.
 
 If you have followed the directions from the prior section on creating a rustup toolchain,

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]: /mir/index.md
-[monomorph]: /appendix/glossary.md#mono
+[mir]: ../mir/index.md
+[monomorph]: ../appendix/glossary.md#mono
 
 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,
@@ -22,9 +22,9 @@ run and that some validation has occurred. Then, it [steals][steal] the MIR,
 optimizes it, and returns the improved MIR.
 
 [optmir]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir_transform/fn.optimized_mir.html
-[query]: /query.md
-[defid]: /appendix/glossary.md#def-id
-[steal]: /mir/passes.md#stealing
+[query]: ../query.md
+[defid]: ../appendix/glossary.md#def-id
+[steal]: ../mir/passes.md#stealing
 
 ## Quickstart for adding a new optimization