Wrap with Obx removes variables from string interpolation

[talski]

When I wrap the following widget with Obx, it modifies the code

FocusTraversalOrder(
    order: LexicalFocusOrder('$colIdx'),
    child: Container(),
)

becomes

Obx(() => FocusTraversalOrder(
      order: LexicalFocusOrder(''),
      child: Container(),
)),