Update 02_FixtureFactories.md

- Removed duplicate `use SilverStripe\Core\Injector\Injector;`
- Changed $myPageObj to $MyObjectObj

docs/en/02_Developer_Guides/06_Testing/How_Tos/02_FixtureFactories.md

@@ -14,7 +14,6 @@ with information that we need.
 
 
 ```php
-use SilverStripe\Core\Injector\Injector;
 use SilverStripe\Dev\SapphireTest;
 use SilverStripe\Core\Injector\Injector;
 
@@ -45,7 +44,7 @@ class MyObjectTest extends SapphireTest
         echo $MyObjectObj->MyProperty;
         // returns "My Default Value"
 
-        echo $myPageObj->MyOtherProperty;
+        echo $MyObjectObj->MyOtherProperty;
         // returns "My Custom Value"
     }
 }