Fix link name of tracking issue keep-going

Author: weihanglo

src/doc/src/reference/unstable.md

@@ -455,7 +455,7 @@ cargo rustc --crate-type lib,cdylib -Z unstable-options
 ```
 
 ### keep-going
-* Tracking Issue: [#0](https://github.com/rust-lang/cargo/issues/10496)
+* Tracking Issue: [#10496](https://github.com/rust-lang/cargo/issues/10496)
 
 `cargo build --keep-going` (and similarly for `check`, `test` etc) will build as
 many crates in the dependency graph as possible, rather than aborting the build