docs: Fix .md syntax typo in header

diff --git a/loader/LoaderAndLayerInterface.md b/loader/LoaderAndLayerInterface.md
index 95c11f1..b559941 100644
--- a/loader/LoaderAndLayerInterface.md
+++ b/loader/LoaderAndLayerInterface.md
@@ -155,7 +155,7 @@
 just link to the name vulkan (libvulkan.so).  A specific Vulkan ABI version can
 also be linked to by applications (e.g. libvulkan.so.1).
 
-####Layer Usage
+#### Layer Usage
 
 Applications desiring Vulkan functionality beyond what the core API offers may
 use various layers or extensions. A layer cannot introduce new Vulkan API