Example code of decodeFile is not work

[matsubara0507]

When use decodeFile, occur compile error.
ref. example code at https://hackage.haskell.org/package/yaml-0.11.11.0/docs/Data-Yaml-TH.html#v:decodeFile

yaml> /path/to/yaml/test/Data/Yaml/THSpec.hs:15:11: error:
yaml>     • Couldn't match expected type: Language.Haskell.TH.Syntax.Code
yaml>                                       Language.Haskell.TH.Syntax.Q Value
yaml>                   with actual type: Language.Haskell.TH.Syntax.Q
yaml>                                       (Language.Haskell.TH.Syntax.TExp a0)
yaml>     • In the expression: decodeFile "test/sample.yaml"
yaml>       In the Template Haskell splice $$(decodeFile "test/sample.yaml")
yaml>       In the first argument of ‘shouldBe’, namely
yaml>         ‘($$(decodeFile "test/sample.yaml") :: Value)’
yaml>    |  
yaml> 15 |       ($$(decodeFile "test/sample.yaml") :: Value) `shouldBe` object ["name" .=  String "John Doe", "age" .= Number 23]
yaml>    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Typed TH splice $$(...) expect type Code Q a instead of Q (TExp a) from GHC 9.0.x.
ref. https://gitlab.haskell.org/ghc/ghc/-/wikis/migration/9.0#typed-th-quotes-and-splices-have-different-types

But, decodeFile have return type Q (TExp a).
So, example code of decodeFile is not work.

I think that should fix example code to $$(Code $ decodeFile "config.yaml") OR change decodeFile's return value to Code Q a (Is the latter not good idea for backward compatibility?).

[snoyberg]

A PR fixing the example would be great, ideally with a comment explaining that GHC 9 changed semantics.