Allow attributes for wrappers

[ValJed]

Fix

When creating a custom node of type wrapper you cannot pass attributes as you could with a classic block type.
Simply fixed by adding a second parameter to the toggleWrap function for attributes, and by passing them to isNodeActive and wrapIn methods.

Then we can use attributes the same way we do with toggleBlockType

  commands ({ type, schema }) {
    return attrs => toggleWrap(type, attrs)
  }

By the way, thanks for the amazing work !!