Change documentation link to the correct section in src/etc/htmldocck.py

Co-authored-by: León Orell Valerian Liehr <[email protected]>

Author: Derukugis

src/etc/htmldocck.py

@@ -3,7 +3,7 @@
 
 r"""
 For documentation and usage instructions, please see
-https://rustc-dev-guide.rust-lang.org/rustdoc-internals.html#dotting-is-and-crossing-ts
+https://rustc-dev-guide.rust-lang.org/rustdoc-internals/rustdoc-test-suite.html
 
 htmldocck.py is a custom checker script for Rustdoc HTML outputs.