Add hie.yaml as root Haskell file (#14617)

Author: LaurentRDC

languages.toml

@@ -1569,7 +1569,7 @@ name = "haskell"
 scope = "source.haskell"
 injection-regex = "hs|haskell"
 file-types = ["hs", "hs-boot", "hsc"]
-roots = ["Setup.hs", "stack.yaml", "cabal.project"]
+roots = ["Setup.hs", "stack.yaml", "cabal.project", "hie.yaml"]
 shebangs = ["runhaskell", "stack"]
 comment-token = "--"
 block-comment-tokens = { start = "{-", end = "-}" }