Update title of button in HTML code for clarity (#9602)

Minor change but it seems a little confusing to call the button "Edit" when you use it to "Save" or "Submit" your changed todo item.

aspnetcore/tutorials/first-web-api/samples/2.0/TodoApi/wwwroot/index.html

@@ -43,7 +43,7 @@
             <input type="hidden" id="edit-id">
             <input type="checkbox" id="edit-isComplete">
             <input type="text" id="edit-name">
-            <input type="submit" value="Edit">
+            <input type="submit" value="Save">
             <a onclick="closeInput()" aria-label="Close">&#10006;</a>
         </form>
     </div>
@@ -65,4 +65,4 @@
             crossorigin="anonymous"></script>
     <script src="site.js"></script>
 </body>
-</html>
+</html>