Renamed main to menu_main

fints4javaAndroidApp/src/main/java/net/dankito/banking/fints4java/android/MainActivity.kt

@@ -72,7 +72,7 @@ class MainActivity : AppCompatActivity() {
 
     override fun onCreateOptionsMenu(menu: Menu): Boolean {
         // Inflate the menu; this adds items to the action bar if it is present.
-        menuInflater.inflate(R.menu.main, menu)
+        menuInflater.inflate(R.menu.menu_main, menu)
 
         return true
     }