Find element by id

Sources/Generator/Content/Element.swift

@@ -594,3 +594,21 @@ extension Element {
         }
     }
 }
+
+extension Element {
+
+    /**
+     Find a page by its page ID within the tree of the element.
+     */
+    func find(_ pageId: String) -> Element? {
+        if self.id == pageId {
+            return self
+        }
+        for child in elements {
+            if let found = child.find(pageId) {
+                return found
+            }
+        }
+        return nil
+    }
+}