C#: Update extensionType expected output.

Author: michaelnebel

csharp/ql/test/library-tests/extension/extensionType.expected

@@ -1,7 +1,7 @@
 extensionTypeReceiverParameter
 | extensions.cs:6:5:16:5 | extension(String) | extensions.cs:6:22:6:22 | s |
-| extensions.cs:25:5:34:5 | extension(Object)<Object> | file://:0:0:0:0 | t |
-| extensions.cs:25:5:34:5 | extension(String)<String> | file://:0:0:0:0 | t |
+| extensions.cs:25:5:34:5 | extension(Object)<Object> | extensions.cs:25:20:25:20 | t |
+| extensions.cs:25:5:34:5 | extension(String)<String> | extensions.cs:25:20:25:20 | t |
 | extensions.cs:25:5:34:5 | extension(T)`1 | extensions.cs:25:20:25:20 | t |
 extensionTypeExtendedType
 | extensions.cs:6:5:16:5 | extension(String) | string |