docs: use glob pattern to match source code docs (#1918)

docs/source/source_code/source_code.rst

@@ -0,0 +1,91 @@
+Source Code
+===========
+We are in process of improving the source code documentation. Code should be documented using Doxygen syntax.
+Some examples exist in `main.h` and `main.cpp`. In order for documentation within the code to appear in the
+rendered docs, the definition of the object must be in a header file, although the documentation itself can (and
+should) be in the source file.
+
+Example Documentation Blocks
+----------------------------
+
+**file.h**
+
+.. code-block:: c
+
+   // functions
+   int main(int argc, char *argv[]);
+
+**file.cpp** (with markdown)
+
+.. code-block:: cpp
+
+   /**
+    * @brief Main application entry point.
+    * @param argc The number of arguments.
+    * @param argv The arguments.
+    *
+    * EXAMPLES:
+    * ```cpp
+    * main(1, const char* args[] = {"hello", "markdown", nullptr});
+    * ```
+    */
+   int main(int argc, char *argv[]) {
+     // do stuff
+   }
+
+**file.cpp** (with ReStructuredText)
+
+.. code-block:: cpp
+
+   /**
+    * @brief Main application entry point.
+    * @param argc The number of arguments.
+    * @param argv The arguments.
+    * @rst
+    * EXAMPLES:
+    *
+    * .. code-block:: cpp
+    *    main(1, const char* args[] = {"hello", "rst", nullptr});
+    * @endrst
+    */
+   int main(int argc, char *argv[]) {
+     // do stuff
+   }
+
+Source
+------
+
+.. toctree::
+   :caption: src
+   :maxdepth: 1
+   :glob:
+
+   src/*
+
+.. toctree::
+   :caption: src/platform
+   :maxdepth: 1
+   :glob:
+
+   src/platform/*
+
+.. toctree::
+   :caption: src/platform/linux
+   :maxdepth: 1
+   :glob:
+
+   src/platform/linux/*
+
+.. toctree::
+   :caption: src/platform/macos
+   :maxdepth: 1
+   :glob:
+
+   src/platform/macos/*
+
+.. toctree::
+   :caption: src/platform/windows
+   :maxdepth: 1
+   :glob:
+
+   src/platform/windows/*