How to specify discard do binds hint?

Hi! I would like to specify the following rule with hlint:

- warn:
    lhs: _ <- foo
    rhs: foo_

However, when I try to run hlint (version 2.2.2), I see the following error:

hlint: user error (Failed to read YAML configuration file ~/haskell/sandbox/.hlint.yaml
  Aeson exception:
Error in $: Error when decoding YAML, Failed to parse Parse error: <-, when parsing:
  _ <- foo
Along path: root 0 warn lhs
When at: String
- warn:
    lhs: _ <- foo
    rhs: foo_
)

Is there any way to specify discarding of monadic computation inside do-block?

Start with the .hlint.yaml configuration shown in the issue and investigate how HLint parses the lhs and rhs values in version 2.2.2. Check whether the discard rule can be represented by the existing hint syntax; done means a valid configuration expresses the rule and runs without the reported YAML parse error.