Rollup merge of #69747 - spastorino:rename-rustc-guide, r=pietroalbini

Rename rustc guide

This is in preparation for https://github.com/rust-lang/rustc-guide/issues/470
Needs to be merged after we actually rename the guide.

Have used this to rename:

`git grep -l 'rustc_guide' | xargs sed -i 's/rustc_guide/rustc_dev_guide/g'`
`git grep -l 'rustc-guide' | xargs sed -i 's/rustc-guide/rustc-dev-guide/g'`
`git grep -l 'rustc guide' | xargs sed -i 's/rustc guide/rustc dev guide/g'`

src/test/COMPILER_TESTS.md

@@ -1,4 +1,4 @@
 # Compiler Test Documentation
 
 Documentation for the compiler testing framework can be found in
-[the rustc guide](https://rust-lang.github.io/rustc-guide/tests/intro.html).
+[the rustc dev guide](https://rustc-dev-guide.rust-lang.org/tests/intro.html).