TextEditor: Do not create proposals for functions without arguments

Change-Id: I5e53bf34a117c8ad877b91868af8817b1d0c8805
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/texteditor/codeassist/keywordscompletionassist.cpp

@@ -205,6 +205,8 @@ IAssistProposal *KeywordsCompletionAssistProcessor::perform(const AssistInterfac
 
     if (m_keywords.isFunction(word) && interface->characterAt(pos) == '(') {
         QStringList functionSymbols = m_keywords.argsForFunction(word);
+        if (functionSymbols.size() == 0)
+            return nullptr;
         IFunctionHintProposalModel *model = new KeywordsFunctionHintModel(functionSymbols);
         return new FunctionHintProposal(startPosition, model);
     } else {