Should only display the confirmation if the shadow tiddler has not been
overridden in the first place. It checks this by looking for the
existence of a modified field for which the default system based shadow
do not have until a user changes them.
This addresses the second line item on issue #570
We will need new translations for the added string
`ConfirmEditShadowTiddler`
Now the $:/ part of the name is rendered in grey, making the main part
of the title more prominent.
@tobibeer suggested this a long time ago; good idea!
