It’s sometimes called comma-leading style where you move all the special characters to the front of the line and it is exceedingly common in Haskell, possibly due to how Haskell treats significant whitespace. You’ve surely seen list definitions that look like this:

someList =
  [ 1
  , 2
  , 3
  ] 

or a data definition like this:

data Color
  = Red
  | Green
  | Blue
  | RGB Int Int Int
  deriving (Show, Eq)

or a list of module exports like this:

module Foo
  { bar
  , baz
  , quux
  } 

Or in a long function type declaration where the arrows are moved to the start of the line, or a record definition, etc. etc.