Define and use function Verbatim...

... in cases of "TranslatableString" that are not really translated.

This makes it easier to scan the code for such unusual constructions of
TranslatableString, distinct from mere mentions of the TranslatableString type.

src/import/Import.cpp

@@ -809,6 +809,6 @@ void ImportFileHandle::CreateProgress()
 
    auto title = XO("Importing %s").Format( GetFileDescription() );
    mProgress = std::make_unique< ProgressDialog >(
-      title, TranslatableString{ ff.GetFullName() } );
+      title, Verbatim( ff.GetFullName() ) );
 }