Document two two .github subdirectories

README.rst

@@ -47,31 +47,31 @@ The RGBDS source code file structure somewhat resembles the following:
 
        .
        ├── .github/
-       │   ├── actions/
-       │   │   └── ...
-       │   └── workflows/
-       │       └── ...
+       │   ├── actions/
+       │   │   └── ...
+       │   └── workflows/
+       │       └── ...
        ├── contrib/
-       │   ├── zsh_compl/
-       │   │   └── ...
-       │   └── ...
+       │   ├── zsh_compl/
+       │   │   └── ...
+       │   └── ...
        ├── include/
-       │   └── ...
+       │   └── ...
        ├── src/
-       │   ├── asm/
-       │   │   └── ...
-       │   ├── extern/
-       │   │   └── ...
-       │   ├── fix/
-       │   │   └── ...
-       │   ├── gfx/
-       │   │   └── ...
-       │   ├── link/
-       │   │   └── ...
-       │   ├── CMakeLists.txt
-       │   └── ...
+       │   ├── asm/
+       │   │   └── ...
+       │   ├── extern/
+       │   │   └── ...
+       │   ├── fix/
+       │   │   └── ...
+       │   ├── gfx/
+       │   │   └── ...
+       │   ├── link/
+       │   │   └── ...
+       │   ├── CMakeLists.txt
+       │   └── ...
        ├── test/
-       │   ├── ...
+       │   ├── ...
        │   └── run-tests.sh
        ├── CMakeLists.txt
        ├── Makefile
@@ -80,6 +80,9 @@ The RGBDS source code file structure somewhat resembles the following:
 - ``.github/`` - files and scripts related to the integration of the RGBDS codebase with
   GitHub.
 
+  * ``actions/`` - scripts used by workflow files.
+  * ``workflows/`` - CI workflow description files.
+
 - ``contrib/`` - scripts and other resources which may be useful to users and developers of
   RGBDS.