TextEditor: De-noise IAssistProcessor derived classes

...by providing a default implementation of immediateProposal() in the
base class.

Change-Id: I4f4f9aa491fbfc9390cc7b7093f1b3c1c8e460a4
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

src/plugins/fakevim/fakevimplugin.cpp

@@ -808,8 +808,6 @@ public:
         : m_provider(static_cast<const FakeVimCompletionAssistProvider *>(provider))
     {}
 
-    IAssistProposal *immediateProposal(const IAssistInterface *) { return 0; }
-
     IAssistProposal *perform(const IAssistInterface *interface)
     {
         const QString &needle = m_provider->needle();