Starts a new completion with the specified GtkSourceCompletionContext and
a list of potential candidate providers for completion.
It can be convenient for showing a completion on-the-fly, without the need to
add or remove providers to the GtkSourceCompletion.
Another solution is to add providers with
gtk_source_completion_add_provider(), and implement
gtk_source_completion_provider_match() for each provider.
Starts a new completion with the specified GtkSourceCompletionContext and a list of potential candidate providers for completion. It can be convenient for showing a completion on-the-fly, without the need to add or remove providers to the GtkSourceCompletion. Another solution is to add providers with gtk_source_completion_add_provider(), and implement gtk_source_completion_provider_match() for each provider.