Starts a new completion with the specified gsv.SourceCompletionContext 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 gsv.SourceCompletion
Another solution is to add providers with Source.completionAddProvider, and implement Source.completionProviderMatch for each provider.
a list of GtkSourceCompletionProvider, or NULL.
The gsv.SourceCompletionContext with which to start the completion.
TRUE if it was possible to the show completion window.
Starts a new completion with the specified gsv.SourceCompletionContext 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 gsv.SourceCompletion
Another solution is to add providers with Source.completionAddProvider, and implement Source.completionProviderMatch for each provider.