CodeAssist: Ensure perfect match for keywords

...as otherwise the completion windows stays open and gets in the way.

Fixes: QTCREATORBUG-21767
Change-Id: Ib0a841b9d9de52109439f067c466478744361814
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/clangcodemodel/clangassistproposalitem.cpp

@@ -489,6 +489,12 @@ QString ClangAssistProposalItem::detail() const
     return detail;
 }
 
+bool ClangAssistProposalItem::isKeyword() const
+{
+    // KeywordCompletionKind includes real keywords but also "code patterns"/snippets.
+    return m_codeCompletions[0].completionKind == CodeCompletion::KeywordCompletionKind;
+}
+
 bool ClangAssistProposalItem::isSnippet() const
 {
     return false;

src/plugins/clangcodemodel/clangassistproposalitem.h

@@ -47,6 +47,7 @@ public:
     QString text() const final;
     QIcon icon() const final;
     QString detail() const final;
+    bool isKeyword() const final;
     bool isSnippet() const final;
     bool isValid() const final;
     quint64 hash() const final;