qt: sweep_key_dialog: make UI a bit more intuitive

user complained:
> when you want to sweep an address. it's very unclear to me as a noob who is getting the money
> might want a little picture with an arrow to show which direction the funds are going

electrum/gui/qt/main_window.py

@@ -2366,12 +2366,13 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger, QtEventListener):
         d.setMinimumSize(600, 300)
         vbox = QVBoxLayout(d)
         hbox_top = QHBoxLayout()
-        hbox_top.addWidget(QLabel(_("Enter private keys:")))
+        hbox_top.addWidget(QLabel(_("Enter private keys to sweep coins from:")))
         hbox_top.addWidget(InfoButton(WIF_HELP_TEXT), alignment=Qt.AlignRight)
         vbox.addLayout(hbox_top)
         keys_e = ScanQRTextEdit(allow_multi=True, config=self.config)
         keys_e.setTabChangesFocus(True)
         vbox.addWidget(keys_e)
+        vbox.addWidget(QLabel(_("Send to address") + ":"))
 
         addresses = self.wallet.get_unused_addresses()
         if not addresses:

electrum/gui/qt/util.py

@@ -572,7 +572,9 @@ class VLine(QFrame):
         self.setLineWidth(1)
 
 
-def address_field(addresses):
+def address_field(addresses, *, btn_text: str = None):
+    if btn_text is None:
+        btn_text = _('Get wallet address')
     hbox = QHBoxLayout()
     address_e = QLineEdit()
     if addresses and len(addresses) > 0:
@@ -590,7 +592,7 @@ def address_field(addresses):
             # address not in the wallet (or to something that isn't an address)
             if addresses and len(addresses) > 0:
                 address_e.setText(addresses[0])
-    button = QPushButton(_('Address'))
+    button = QPushButton(btn_text)
     button.clicked.connect(func)
     hbox.addWidget(button)
     hbox.addWidget(address_e)