Documentation Update: Add from and to usage examples to migration scr…

…ipt samples (#2142)

* Add from and to usage examples to migration script samples

Add from and to usage examples to migration script samples on the Migrations page under the General SQL Scripts section.

* removed -From and -To to keep consistency

entity-framework/core/managing-schemas/migrations/index.md

@@ -209,16 +209,44 @@ When debugging your migrations or deploying them to a production database, it's
 
 ### [.NET Core CLI](#tab/dotnet-core-cli)
 
+#### Basic Usage
 ```dotnetcli
 dotnet ef migrations script
 ```
 
+#### With From (to implied)
+This will generate a SQL script from this migration to the latest migration.
+```dotnetcli
+dotnet ef migrations script 20190725054716_Add_new_tables
+```
+
+#### With From and To
+This will generate a SQL script from the `from` migration to the specified `to` migration.
+```dotnetcli
+dotnet ef migrations script 20190725054716_Add_new_tables 20190829031257_Add_audit_table
+```
+You can use a `from` that is newer than the `to` in order to generate a rollback script. *Please take note of potential data loss scenarios.*
+
 ### [Visual Studio](#tab/vs)
 
+#### Basic Usage
 ``` powershell
 Script-Migration
 ```
 
+#### With From (to implied)
+This will generate a SQL script from this migration to the latest migration.
+```powershell
+Script-Migration 20190725054716_Add_new_tables
+```
+
+#### With From and To
+This will generate a SQL script from the `from` migration to the specified `to` migration.
+```powershell
+Script-Migration 20190725054716_Add_new_tables 20190829031257_Add_audit_table
+```
+You can use a `from` that is newer than the `to` in order to generate a rollback script. *Please take note of potential data loss scenarios.*
+
 ***
 
 There are several options to this command.