Use link definition for existing "brace syntax" link

In the prior commit, we added a link reference definition for "brace
syntax". Let's update the other use in the chapter to use that.

Author: traviscross

src/items/use-declarations.md

@@ -182,7 +182,7 @@ r[items.use.self]
 ## `self` imports
 
 r[items.use.self.intro]
-The keyword `self` may be used within [brace syntax](#brace-syntax) to create a binding of the parent entity under its own name.
+The keyword `self` may be used within [brace syntax] to create a binding of the parent entity under its own name.
 
 ```rust
 mod stuff {