List of arches that support -Zsanitizer=shadow-call-stack is incomplete

[Darksonn]

Location

This issue is in the list of sanitizers at src/doc/unstable-book/src/compiler-flags/sanitizer.md.

Summary

Currently, the documentation says that aarch64-linux-android is the only target that supports shadow call stack. However, as of #106061, there are some Fuchsia targets that also support it. The list should be extended to list all targets that support the feature.