Improve lambda case

[Futarimiti]

Correctly indent further cases for a lambda case expression where the first pattern is on the same line as \case.

Examples:

lambda_case :: Maybe Int -> Int
lambda_case = \case Nothing -> 0
>>>>>>>>>>>>>>>>>>>>Just n -> n

lambda_case2 :: (Bool, Bool) -> Int
lambda_case2 = \case(True,True)->1
>>>>>>>>>>>>>>>>>>>>(_, False) -> 3

[Futarimiti]

Let me know if you want me to add tests as well, or make use of g:haskell_indent_disable_case

[itchyny]

Yes, please add tests.

[Futarimiti]

Just found out \ case would be valid lambda case as well, which is not covered here

[Futarimiti]

Good enough I believe. Take a look! @itchyny

[itchyny]

Thank you!