Fixing guide example on 2 indent levels for continuation lines

The original example seems to be using 3 tabs for indentation, but the description said 2 should be used.

tutorials/scripting/gdscript/gdscript_styleguide.rst

@@ -153,8 +153,8 @@ regular code blocks.
 ::
 
     effect.interpolate_property(sprite, "transform/scale",
-                sprite.get_scale(), Vector2(2.0, 2.0), 0.3,
-                Tween.TRANS_QUAD, Tween.EASE_OUT)
+            sprite.get_scale(), Vector2(2.0, 2.0), 0.3,
+            Tween.TRANS_QUAD, Tween.EASE_OUT)
 
 **Bad**: