ClangCodeModel: Fix template highlighting bug

We need to take into account that the ">>" in constructs such as
std::vector<std::pair<int, int>> is only one token on the clang side.

Change-Id: I90f002ca56f236032f6d39c338593a2ff7590061
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: David Schulz <david.schulz@qt.io>

tests/unit/unittest/data/highlightingmarks.cpp

@@ -769,3 +769,5 @@ template<typename T>
 void func(T v) {
     GlobalVar = 5;
 }
+
+static std::vector<std::pair<int, int>> pv;