package/qt5/qt5virtualkeyboard: add an upstream URL to Config.in

Add an upstream URL to the help text in Config.in. This
addresses the 'Missing' URL status in the package stats
web page output.

Signed-off-by: Mark Corbin <mark@dibsco.co.uk>
Reviewed-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/qt5/qt5virtualkeyboard/Config.in

@@ -14,6 +14,8 @@ config BR2_PACKAGE_QT5VIRTUALKEYBOARD
 	  consists of a C++ backend supporting custom input methods as
 	  well as a UI frontend implemented in QML.
 
+	  https://doc.qt.io/qt-5/qtvirtualkeyboard-index.html
+
 if BR2_PACKAGE_QT5VIRTUALKEYBOARD
 
 config BR2_PACKAGE_QT5VIRTUALKEYBOARD_LANGUAGE_LAYOUTS