Fixed HTML escaping issues in the function argument widget

HTML escaping was moved out of the TypePrettyPrinter since it interferes
with other logic there. Instead, the region to mark is now available
from the Overview and used by the FunctionArgumentWidget to put the
current argument in bold.

src/libs/cplusplus/Overview.cpp

@@ -35,27 +35,18 @@
 using namespace CPlusPlus;
 
 Overview::Overview()
-    : _markArgument(0),
+    : _markedArgument(0),
+      _markedArgumentBegin(0),
+      _markedArgumentEnd(0),
       _showArgumentNames(false),
       _showReturnTypes(false),
       _showFunctionSignatures(true),
-      _showFullyQualifiedNames(false),
-      _richText(false)
+      _showFullyQualifiedNames(false)
 { }
 
 Overview::~Overview()
 { }
 
-bool Overview::richText() const
-{
-    return _richText;
-}
-
-void Overview::setRichText(bool richText)
-{
-    _richText = richText;
-}
-
 bool Overview::showArgumentNames() const
 {
     return _showArgumentNames;
@@ -76,14 +67,34 @@ bool Overview::showReturnTypes() const
     return _showReturnTypes;
 }
 
-unsigned Overview::markArgument() const
+unsigned Overview::markedArgument() const
 {
-    return _markArgument;
+    return _markedArgument;
 }
 
-void Overview::setMarkArgument(unsigned position)
+void Overview::setMarkedArgument(unsigned position)
 {
-    _markArgument = position;
+    _markedArgument = position;
+}
+
+int Overview::markedArgumentBegin() const
+{
+    return _markedArgumentBegin;
+}
+
+void Overview::setMarkedArgumentBegin(int begin)
+{
+    _markedArgumentBegin = begin;
+}
+
+int Overview::markedArgumentEnd() const
+{
+    return _markedArgumentEnd;
+}
+
+void Overview::setMarkedArgumentEnd(int end)
+{
+    _markedArgumentEnd = end;
 }
 
 bool Overview::showFunctionSignatures() const