Fix spelling, update comments.

Include/RmlUi/Core/RenderInterface.h

@@ -64,8 +64,8 @@ public:
 	virtual void RenderGeometry(Vertex* vertices, int num_vertices, int* indices, int num_indices, TextureHandle texture, const Vector2f& translation) = 0;
 
 	/// Called by RmlUi when it wants to compile geometry it believes will be static for the forseeable future.
-	/// If supported, this should be return a pointer to an optimised, application-specific version of the data. If
-	/// not, do not override the function or return nullptr; the simpler RenderGeometry() will be called instead.
+	/// If supported, this should return a handle to an optimised, application-specific version of the data. If
+	/// not, do not override the function or return zero; the simpler RenderGeometry() will be called instead.
 	/// @param[in] vertices The geometry's vertex data.
 	/// @param[in] num_vertices The number of vertices passed to the function.
 	/// @param[in] indices The geometry's index data.
@@ -108,7 +108,8 @@ public:
 	virtual void ReleaseTexture(TextureHandle texture);
 
 	/// Called by RmlUi when it wants the renderer to use a new transform matrix.
-	/// If no transform applies to the current element, nullptr is submitted. Then it expects the renderer to use an identity matrix or otherwise omit the multiplication with the transform.
+	/// This will only be called if 'transform' properties are encountered. If no transform applies to the current element, nullptr
+	/// is submitted. Then it expects the renderer to use an identity matrix or otherwise omit the multiplication with the transform.
 	/// @param[in] transform The new transform to apply, or nullptr if no transform applies to the current element.
 	virtual void SetTransform(const Matrix4f* transform);