Fix typos in GLTFViewer and Tutorial21

Author: TheMostDiligent

Samples/GLTFViewer/src/GLTFViewer.cpp

@@ -935,7 +935,7 @@ void GLTFViewer::UpdateUI()
         {
             std::array<const char*, static_cast<size_t>(BackgroundMode::NumModes)> BackgroundModes;
             BackgroundModes[static_cast<size_t>(BackgroundMode::None)]              = "None";
-            BackgroundModes[static_cast<size_t>(BackgroundMode::EnvironmentMap)]    = "Environmen Map";
+            BackgroundModes[static_cast<size_t>(BackgroundMode::EnvironmentMap)]    = "Environment Map";
             BackgroundModes[static_cast<size_t>(BackgroundMode::Irradiance)]        = "Irradiance";
             BackgroundModes[static_cast<size_t>(BackgroundMode::PrefilteredEnvMap)] = "PrefilteredEnvMap";
             ImGui::Combo("Background mode", reinterpret_cast<int*>(&m_BackgroundMode), BackgroundModes.data(), static_cast<int>(BackgroundModes.size()));

Tutorials/Tutorial21_RayTracing/readme.md

@@ -200,7 +200,7 @@ You may add more ray types, e.g. a secondary ray that uses simplified hit shader
 
 `BindingMode` is the hit group location calculation mode. In our example we will be assigning different 
 hit groups to different instances, so we use the `HIT_GROUP_BINDING_MODE_PER_INSTANCE` mode. If an application 
-needs more control, it can use `HIT_GROUP_BINDING_MODE_PER_GEOMETRY` mode to assign indiviudal hit group to 
+needs more control, it can use `HIT_GROUP_BINDING_MODE_PER_GEOMETRY` mode to assign individual hit group to 
 each geometry within every instance. On the other hand, it can use `HIT_GROUP_BINDING_MODE_PER_TLAS` mode 
 to assign the same hit group to all geometries in all instances.