Fix vertex buffer/shader mixup

Author: Overv

en/04_Vertex_buffers/03_Index_buffer.md

@@ -148,7 +148,7 @@ vkCmdDrawIndexed(commandBuffer, static_cast<uint32_t>(indices.size()), 1, 0, 0,
 A call to this function is very similar to `vkCmdDraw`. The first two parameters
 specify the number of indices and the number of instances. We're not using
 instancing, so just specify `1` instance. The number of indices represents the
-number of vertices that will be passed to the vertex buffer. The next parameter
+number of vertices that will be passed to the vertex shader. The next parameter
 specifies an offset into the index buffer, using a value of `1` would cause the
 graphics card to start reading at the second index. The second to last parameter
 specifies an offset to add to the indices in the index buffer. The final