explicitly name functions in strings

src/main/java/com/sparrowwallet/sparrow/wallet/Function.java

@@ -1,5 +1,15 @@
 package com.sparrowwallet.sparrow.wallet;
 
 public enum Function {
-    TRANSACTIONS, SEND, RECEIVE, ADDRESSES, UTXOS, SETTINGS, LOCK;
+    TRANSACTIONS("transactions"), SEND("send"), RECEIVE("receive"), ADDRESSES("addresses"), UTXOS("utxos"), SETTINGS("settings"), LOCK("lock");
+
+    private final String name;
+
+    Function(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return name;
+    }
 }

src/main/java/com/sparrowwallet/sparrow/wallet/WalletController.java

@@ -90,9 +90,9 @@ public class WalletController extends WalletFormController implements Initializa
 
             try {
                 if(!existing) {
-                    URL url = AppServices.class.getResource("wallet/" + function.toString().toLowerCase() + ".fxml");
+                    URL url = AppServices.class.getResource("wallet/" + function.getName() + ".fxml");
                     if(url == null) {
-                        url = AppServices.class.getResource("wallet" + File.separator + function.toString().toLowerCase() + ".fxml");
+                        url = AppServices.class.getResource("wallet" + File.separator + function.getName() + ".fxml");
                     }
                     if(url == null) {
                         throw new IllegalStateException("Cannot find wallet/" + function.toString().toLowerCase() + ".fxml");