Small fixes in extensions docs (#8934)

docs/IE_DG/Extensibility_DG/Extension.md

@@ -10,7 +10,7 @@ Based on that, the declaration of an extension class can look as follows:
 
 @snippet template_extension/old/extension.hpp extension:header
 
-The extension library should contain and export the InferenceEngine::CreateExtension method, which creates an `Extension` class:
+The extension library should use `IE_DEFINE_EXTENSION_CREATE_FUNCTION` macro to export a function, which creates an `Extension` class:
 
 @snippet template_extension/old/extension.cpp extension:CreateExtension
 

docs/IE_DG/Extensibility_DG/Intro.md

@@ -2,7 +2,7 @@
 
 Inference Engine Extensibility API enables you to add support of custom operations to the Inference Engine.
 Extension should contain operation sets with custom operations and execution kernels for custom operations.
-Physically, an extension library can be represented as a dynamic library exporting the single `CreateExtension` function
+Physically, an extension library can be represented as a dynamic library exporting the single function
 that creates a new extension instance.
 
 To load the Extensibility library to the `InferenceEngine::Core` object, use the