Clang: Do not show diagnostic category in inline annotations and issues pane

For build system diagnostics they are not displayed either.

Also, the error/warning is already encoded in the icon and the color.

However, the category is still shown in the tooltip.

Change-Id: I190ab17691c32786cefc20d058010c65cda5ace9
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/clangcodemodel/clangutils.cpp

@@ -307,5 +307,30 @@ CPlusPlus::Icons::IconType iconTypeForToken(const ClangBackEnd::TokenInfoContain
     return CPlusPlus::Icons::UnknownIconType;
 }
 
+QString diagnosticCategoryPrefixRemoved(const QString &text)
+{
+    QString theText = text;
+
+    // Prefixes are taken from $LLVM_SOURCE_DIR/tools/clang/lib/Frontend/TextDiagnostic.cpp,
+    // function TextDiagnostic::printDiagnosticLevel (llvm-3.6.2).
+    static const QStringList categoryPrefixes = {
+        QStringLiteral("note"),
+        QStringLiteral("remark"),
+        QStringLiteral("warning"),
+        QStringLiteral("error"),
+        QStringLiteral("fatal error")
+    };
+
+    for (const QString &prefix : categoryPrefixes) {
+        const QString fullPrefix = prefix + QStringLiteral(": ");
+        if (theText.startsWith(fullPrefix)) {
+            theText.remove(0, fullPrefix.length());
+            return theText;
+        }
+    }
+
+    return text;
+}
+
 } // namespace Utils
 } // namespace Clang