Values.BlockReferenceSourceA reference to a block.
type nonrec t = {blockId : String_.t option;Unique identifier for the block.
*)beginOffset : Integer.t option;Offset of the start of the block within its parent block.
*)endOffset : Integer.t option;Offset of the end of the block within its parent block.
*)childBlocks : ListOfChildBlocks.t option;List of child blocks within this block.
*)}