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.

src/items/use-declarations.md

diff --git a/src/items/use-declarations.md b/src/items/use-declarations.md
index 6ffab8f..9449fab 100644
--- a/src/items/use-declarations.md
+++ b/src/items/use-declarations.md
@@ -182,7 +182,7 @@
 ## `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 {