D12420: Make the warning text for deletion operations emphasize its permanency and irreversibility

[Nathaniel Graham]

ngraham added a dependent revision: D12422: Use a regular dialog rather than a 
list dialog when trashing or deleting a single file.

REPOSITORY
  R241 KIO

REVISION DETAIL
  https://phabricator.kde.org/D12420

To: ngraham, #frameworks, #dolphin, elvisangelaccio
Cc: michaelh, bruns