ClangCodeModel: Ignore number literals

... in the semantic highlighter. The syntax highlighter already handles
these.

Change-Id: I26f6bca06c4fc648ffe59bd9e3639d81d2265755
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/cppeditor/testcases/highlightingtestcase.cpp

@@ -12,3 +12,12 @@ void keywords()
     bool b2 = false;
     void *p = nullptr;
 }
+
+void numberLiterals()
+{
+    auto integer         = 1;
+    auto numFloat1       = 1.2f;
+    auto numFloat2       = 1.2;
+}
+
+template<int n = 5> class C;