Rollup merge of #76858 - rcvalle:rust-lang-exploit-mitigations, r=steveklabnik

Add exploit mitigations chapter to the rustc book

This section documents the exploit mitigations applicable to the Rust compiler when building programs for the Linux operating system on the AMD64 architecture and equivalent. This was done for a project I'm currently working on, and I hope it'll also be helpful to others.

Author: jonas-schievink

src/doc/rustc/src/SUMMARY.md

@@ -18,4 +18,5 @@
     - [Known Issues](targets/known-issues.md)
 - [Profile-guided Optimization](profile-guided-optimization.md)
 - [Linker-plugin based LTO](linker-plugin-lto.md)
+- [Exploit Mitigations](exploit-mitigations.md)
 - [Contributing to `rustc`](contributing.md)