Syntax highlighting glitch for @keydown.+=""

[vincesp]

When registering keydown handlers for the plus and minus keys, then there is a glitch in the code highlighting.

This is my code:

<FileItem
  @keydown.left="item.expanded = false"
  @keydown.right="item.expanded = true"
  @keydown.-="item.expanded = false"
  @keydown.+="item.expanded = true"
></FileItem>

Result:

While the highlighting is correct for the minus key, it seems off for the plus key.