Added test case documentation generator

docs/test_cases/t00012.md

@@ -0,0 +1,59 @@
+# t00012 - Advanced template instantiations
+## Config
+```yaml
+compilation_database_dir: ..
+output_directory: puml
+diagrams:
+  t00012_class:
+    type: class
+    glob:
+      - ../../tests/t00012/t00012.cc
+    using_namespace:
+      - clanguml::t00012
+    include:
+      namespaces:
+        - clanguml::t00012
+
+```
+## Source code
+```cpp
+#include <algorithm>
+#include <map>
+#include <numeric>
+#include <string>
+#include <variant>
+#include <vector>
+
+namespace clanguml {
+namespace t00012 {
+
+template <typename T, typename... Ts> class A {
+    T value;
+    std::variant<Ts...> values;
+};
+
+template <int... Is> class B {
+    std::array<int, sizeof...(Is)> ints;
+};
+
+template <typename T, int... Is> class C {
+    std::array<T, sizeof...(Is)> ints;
+};
+
+class R {
+    A<int, std::string, float> a1;
+    A<int, std::string, bool> a2;
+
+    B<3, 2, 1> b1;
+    B<1, 1, 1, 1> b2;
+
+    C<std::map<int, std::vector<std::vector<std::vector<std::string>>>>, 3, 3,
+        3>
+        c1;
+};
+}
+}
+
+```
+## Generated UML diagrams
+![t00012_class](./t00012_class.png "Advanced template instantiations")