add markdown and put back Pipeline::Release()

as asked by rpavlik

Author: remmel

changes/sdk/pr.538.gh.OpenXR-SDK-Source.md

@@ -0,0 +1 @@
+> hello_xr: Fix Vulkan resource destruction bugs of ShaderProgram and Pipeline.

src/tests/hello_xr/graphicsplugin_vulkan.cpp

@@ -871,7 +871,7 @@ struct Pipeline {
         CHECK_VKCMD(vkCreateGraphicsPipelines(m_vkDevice, VK_NULL_HANDLE, 1, &pipeInfo, nullptr, &pipe));
     }
 
-    ~Pipeline() {
+    void Release() {
         if (m_vkDevice != nullptr) {
             if (pipe != VK_NULL_HANDLE) {
                 vkDestroyPipeline(m_vkDevice, pipe, nullptr);
@@ -881,6 +881,8 @@ struct Pipeline {
         m_vkDevice = nullptr;
     }
 
+    ~Pipeline() { Release(); }
+
    private:
     VkDevice m_vkDevice{VK_NULL_HANDLE};
 };