KetraTermsetShellSuggestionFailureHandler
Selects provider diagnostics for this view on the EDT; null restores logging.
Reports each current provider failure once, after cancelling its work and hiding suggestions. Cancellation and obsolete requests are excluded. The callback runs on the EDT and may start a new request. Disposal releases it; rebinding retains the view-owned handler. Callback failures are logged, while callback cancellation propagates.
Throws
when called outside the EDT or after disposal.