Updated test cases documentation

docs/test_cases/t30009.md

@@ -0,0 +1,50 @@
+# t30009 - Together layout hint test
+## Config
+```yaml
+compilation_database_dir: ..
+output_directory: puml
+diagrams:
+  t30009_package:
+    type: package
+    glob:
+      - ../../tests/t30009/t30009.cc
+    include:
+      namespaces:
+        - clanguml::t30009
+    using_namespace:
+      - clanguml::t30009
+    layout:
+      One::A:
+        - together: [One::C]
+      Two::B:
+        - together: [Two::C, Two::D]
+```
+## Source code
+File t30009.cc
+```cpp
+namespace clanguml::t30009 {
+namespace One {
+namespace A {
+}
+namespace B {
+}
+namespace C {
+}
+namespace D {
+}
+}
+namespace Two {
+namespace A {
+}
+namespace B {
+}
+namespace C {
+}
+namespace D {
+}
+}
+}
+
+```
+## Generated UML diagrams
+![t30009_package](./t30009_package.svg "Together layout hint test")