Utilzie url keyboard when entering text into the proxy input.

app/src/main/res/layout/edit_proxy_fragment.xml

@@ -67,6 +67,7 @@
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:hint="@string/preferences_enter_proxy_address"
+      android:inputType="textUri"
       android:layout_marginHorizontal="16dp"
       app:layout_constraintTop_toBottomOf="@id/edit_proxy_address_title"
       tools:hint="https://proxy.parker.org"/>