Fix usage of backquotes with word characters on either side.

Fixes KhronosGroup#212

Author: oddhack

en/03_Drawing_a_triangle/00_Setup/01_Instance.adoc

@@ -170,10 +170,9 @@ https://vulkan.lunarg.com/doc/sdk/1.3.216.0/mac/getting_started.html[Getting Sta
 Beginning with the 1.3.216 Vulkan SDK, the `VK_KHR_PORTABILITY_subset`
 extension is mandatory.
 
-To get over this error, first add the
- `vk::InstanceCreateFlagBits::eEnumeratePortabilityKHR` bit
+To get over this error, first add the `vk::InstanceCreateFlagBits::eEnumeratePortabilityKHR` bit
 to `VkInstanceCreateInfo` struct flags, then add
-`vk::KHRPortabilityEnumerationExtensionName`to instance enabled
+`vk::KHRPortabilityEnumerationExtensionName` to instance enabled
 extension list.
 
 Typically, the code could be like this:

en/03_Drawing_a_triangle/01_Presentation/01_Swap_chain.adoc

@@ -505,7 +505,7 @@ image::/images/swap_chain_validation_layer.png[]
 
 == Retrieving the swap chain images
 The swap chain has been created now, so all that remains is retrieving the
-handles of the `VkImage`s in it. We'll reference these during rendering
+handles of the ``VkImage``s in it. We'll reference these during rendering
 operations in later chapters.
 
 [,c++]