fix two tests

Author: steveklabnik

src/rust-next/const-fn.md

@@ -74,7 +74,7 @@ enum Error {
 const fn foo() {
     let array = [1, 2, 3];
 
-    let struct = Point {
+    let point = Point {
         x: 5,
         y: 10,
     };
@@ -129,7 +129,7 @@ struct Point {
 }
 
 const fn foo() {
-    let struct = Point {
+    let point = Point {
         x: 5,
         y: 10,
     };