Fix "Deprecated API" header
RELNOTES: None.
@@ -363,7 +363,7 @@ foo = _foo
This way, the name is still re-exported but doesn't generate a warning.
-### Deprecated API [deprecated-api]
+### Deprecated API
See [documentation](https://docs.bazel.build/versions/master/skylark/lib/ctx.html)
for more information.
