message: use indented code blocks
  to be consistent with the rest of the documentation
diff: @@ -17,7 +17,6 @@ Previously, the workflow was to create an object, fill it with the necessary
  parameters, and then place the object into an `OSPModel` via, for example,
  `ospAddGeometry`. An example is shown below using the C API.
  -```cpp
  OSPGeometry mesh = ospNewGeometry("triangles");
  // set parameters on mesh
  ospCommit(mesh);
  @@ -26,7 +25,6 @@ OSPModel world = ospNewModel();
  ospAddGeometry(world, mesh);
  ospRelease(mesh);
  ospCommit(world);
  -```
  In OSPRay 2.0.0, there is now an `OSPWorld`, which effectively replaces the old
  `OSPModel`. In addition, there are now 3 new objects that exist "in between"
  @@ -37,7 +35,6 @@ objects.
  The new workflow is shown below. Note that calls to `ospRelease()` have been
  removed for brevity.
  -```cpp
  // create a geometry
  OSPGeometry mesh = ospNewGeometry("triangles");
  // set parameters on mesh
  @@ -62,7 +59,6 @@ OSPWorld world = ospNewWorld();
  OSPData instances = ospNewSharedData1D(&instance, OSP_INSTANCE, 1);
  ospSetData(world, "instance", instances);
  ospCommit(world);
  -```
  While this looks more complex at first, the new hierarchy structure
  provides more fine control over transformations and instances.
  