minor doc updates

- import of FBX model prefabs is by FBX importer

Author: vkovec

proto.com.unity.formats.fbx/Documentation~/nested-prefabs.md

@@ -2,7 +2,7 @@
 
 > ***Note:*** Prefab Variants are only available in Unity version 2018.3. If you are using Unity version 2018.2, use [Linked Prefabs](prefabs.md) instead. 
 
-When a user imports a Model from a 3D modeling application such as Autodesk® Maya®, it is represented in Unity as a *Model Prefab*. You can't edit Model Prefabs in Unity, apart from [changing the import settings](https://docs.unity3d.com/2018.3/Documentation/Manual/class-FBXImporter.html). If someone saves changes to that Model file in an external application, the FBX Exporter automatically updates the imported Model Prefab. 
+When a user imports a Model from a 3D modeling application such as Autodesk® Maya®, it is represented in Unity as a *Model Prefab*. You can't edit Model Prefabs in Unity, apart from [changing the import settings](https://docs.unity3d.com/2018.3/Documentation/Manual/class-FBXImporter.html). If someone saves changes to that Model file in an external application, the FBX Importer automatically updates the imported Model Prefab. 
 
 ![A Model Prefab in the Scene and Hierarchy views](images/FBXExporter_ModelPrefab.png)
 

proto.com.unity.formats.fbx/Documentation~/prefabs-overview.md

@@ -4,13 +4,13 @@ In version 2018.3, Unity introduced a new way of working with Prefabs: [Nested P
 
 ## Linked Prefabs (Unity 2018.2)
 
-If you are working in Unity version 2018.2, you can use set up an automatic connection between Unity and your 3D modeling application using a Linked Prefab. A Linked Prefab is a script that detects changes that were made to a "linked" FBX file in one application and then seamlessly updates the data in the other application. Once you establish the connection, you generally don't have to re-create the connection to bring in any updates.
+If you are working in Unity version 2018.2, you can set up an automatic connection between Unity and your 3D modeling application using a Linked Prefab. A Linked Prefab is a script that detects changes that were made to a "linked" FBX file in one application and then seamlessly updates the data in the other application. Once you establish the connection, you generally don't have to re-create the connection to bring in any updates.
 
 * For more information, see [Working with Linked Prefabs](prefabs.md).
 
 ## Model Prefab Variants (2018.3)
 
-In Unity version 2018.3, when you open an FBX file in Unity, the FBX Exporter creates a Model Prefab. Model Prefabs are read-only, but you can create a *Prefab Variant* of that Model Prefab. Prefab Variants are Prefabs which inherit all data from a base Prefab. Prefab Variants can create inheritance between ordinary Prefabs. For example, you can create a Variant of a button Prefab which has a different color but the same functionality. 
+In Unity version 2018.3, when you open an FBX file in Unity, the FBX Importer creates a Model Prefab. Model Prefabs are read-only, but you can create a *Prefab Variant* of that Model Prefab. Prefab Variants are Prefabs which inherit all data from a base Prefab. Prefab Variants can create inheritance between ordinary Prefabs. For example, you can create a Variant of a button Prefab which has a different color but the same functionality. 
 
 Since Prefab Variants allow you to override its base Prefab's properties, you can use a Model Prefab Variant to add components, Materials, or change most other property values without affecting the original FBX file.