%^backend{} syntax not valid

[joshuataylor]

Describe the bug
When using this syntax:

      %DataFrame{data: %^backend{}} ->

it causes the editor to lose highlighting, as it's not valid

See this code: https://github.com/elixir-nx/explorer/blob/main/lib/explorer/data_frame.ex#L596

To Reproduce
Steps to reproduce the behavior:

1. Copy in the file above
2. Open it in IntellIJ Elixir
3. Scroll down to the line
4. See error

Expected behavior
Does not error

Screenshots

Logs
If reporting a hang or other performance issue, please attach the thread dumps.

Desktop:

• OS: ArchLinux (btw)
• IntelliJ IDEA 2022.1.3 (Ultimate Edition)

Erlang:

• Installer: compiled
• Version 25.0.1

Elixir:

• Installer: compiled
• Version: 1.13.4

Plugin:

• Version: v13.1.1

Additional context
First time I've seen this syntax 😬