docs: correct alphabetization in 03-landmarks/solution.ts

Author: JoshuaKGoldberg

projects/interfaces/vacation-planning/03-landmarks/solution.ts

@@ -17,16 +17,16 @@ export interface Lighthouse extends BaseLandmark {
 	type: "lighthouse";
 }
 
-export interface Park extends BaseLandmark {
-	acres: number;
-	type: "park";
-}
-
 export interface Mountain extends BaseLandmark {
 	height: number;
 	type: "mountain";
 }
 
+export interface Park extends BaseLandmark {
+	acres: number;
+	type: "park";
+}
+
 export interface River extends BaseLandmark {
 	depth: number;
 	length: number;