RemoteLinux: Add tooltip for line edit

The line edit for the gdb server executable has a
placeholder text that is not readable due to the length
of the text. Add a tooltip that duplicates this text,
but is able to display it completely.

Change-Id: I1c15416f3b31420967825f1b99582021938d3628
Reviewed-by: hjk <hjk@qt.io>

src/plugins/remotelinux/genericlinuxdeviceconfigurationwidget.cpp

@@ -78,6 +78,7 @@ GenericLinuxDeviceConfigurationWidget::GenericLinuxDeviceConfigurationWidget(
             this, &GenericLinuxDeviceConfigurationWidget::gdbServerEditingFinished);
     connect(m_ui->hostKeyCheckBox, &QCheckBox::toggled,
             this, &GenericLinuxDeviceConfigurationWidget::hostKeyCheckingChanged);
+    m_ui->gdbServerLineEdit->setToolTip(m_ui->gdbServerLineEdit->placeholderText());
 
     initGui();
 }