book: Fix broken link to unsafe chapter

diff --git a/src/doc/trpl/const-and-static.md b/src/doc/trpl/const-and-static.md
index a9d33ccf1f30ddc5c1eb1743712a1d29a1295fbb..57cbb6213963a9dff2fe4688912122767926c59b 100644 (file)
--- a/src/doc/trpl/const-and-static.md
+++ b/src/doc/trpl/const-and-static.md
@@ -66,6 +66,8 @@ unsafe {
 }
 ```
 
+[unsafe]: unsafe.html
+
 Furthermore, any type stored in a `static` must be `Sync`.
 
 # Initializing