qt: Show hint if passphrase is shown and formatting is enabled
* qt/pinentrydialog.cpp (PinEntryDialog::PinEntryDialog): Initialize new fields. (PinEntryDialog::PinEntryDialog): Add new widgets to GUI. (PinEntryDialog::setFormattedPassphrase): Set text of the hint. (PinEntryDialog::toggleFormattedPassphrase): Show/hide hint and spacer as needed. * qt/pinentrydialog.h (PinEntryDialog): Add fields mFormattedPassphraseHint, mFormattedPassphraseHintSpacer.
The spacer is used to avoid unnecessary layout changes. It ensures that
the vertical space taken by the hint is retained when the hint is hidden.
- GnuPG-bug-id: T5517