Fix broken links in documentation

graphics/src/cached.rs

@@ -0,0 +1,33 @@
+use crate::Primitive;
+
+use std::sync::Arc;
+
+/// A piece of data that can be cached.
+pub trait Cached: Sized {
+    /// The type of cache produced.
+    type Cache;
+
+    /// Loads the [`Cache`] into a proper instance.
+    ///
+    /// [`Cache`]: Self::Cache
+    fn load(cache: &Self::Cache) -> Self;
+
+    /// Caches this value, producing its corresponding [`Cache`].
+    ///
+    /// [`Cache`]: Self::Cache
+    fn cache(self) -> Self::Cache;
+}
+
+impl<T> Cached for Primitive<T> {
+    type Cache = Arc<Self>;
+
+    fn load(cache: &Arc<Self>) -> Self {
+        Self::Cache {
+            content: cache.clone(),
+        }
+    }
+
+    fn cache(self) -> Arc<Self> {
+        Arc::new(self)
+    }
+}