Enabled accessing comments from system headers in sequence diagrams

tests/t20002/t20002.cc

@@ -1,7 +1,3 @@
-#include <algorithm>
-#include <numeric>
-#include <vector>
-
 namespace clanguml {
 namespace t20002 {
 

tests/t20055/.clang-uml

@@ -10,6 +10,7 @@ diagrams:
           - clanguml::t20055::ns2
         elements:
           - clanguml::t20055::ns1::B
+          - clanguml::t20055::ns1::d()
     using_namespace: clanguml::t20055
     from:
       - function: "clanguml::t20055::ns2::tmain()"

tests/t20055/t20055.cc

@@ -2,13 +2,19 @@ namespace clanguml {
 namespace t20055 {
 namespace ns1 {
 
+void d() { }
+
 struct A {
     void a() { }
 };
 
 struct B {
     A a;
-    void b() { a.a(); }
+    void b()
+    {
+        a.a();
+        d();
+    }
 };
 
 } // namespace ns1

tests/t20055/test_case.h

@@ -30,6 +30,7 @@ TEST_CASE("t20055")
                 //
                 {{"ns2", "tmain()"}, {"ns2", "C"}, "c()"},
                 {{"ns2", "C"}, {"ns1", "B"}, "b()"},
+                {{"ns1", "B"}, {"ns1", "d()"}, ""},
                 {{"ns2", "C"}, {"ns2", "f()"}, ""}
                 //
             }));