haskell: Extract to zed-extensions/haskell repository (#26306)

This PR extracts the Haskell extension to the
[zed-extensions/haskell](https://github.com/zed-extensions/haskell)
repository.

Release Notes:

- N/A

Author: maxdeviant

Cargo.lock

@@ -171,7 +171,6 @@ members = [
 
     "extensions/emmet",
     "extensions/glsl",
-    "extensions/haskell",
     "extensions/html",
     "extensions/perplexity",
     "extensions/proto",

Cargo.toml

@@ -1,6 +1,6 @@
 # Haskell
 
-Haskell support is available through the [Haskell extension](https://github.com/zed-industries/zed/tree/main/extensions/haskell).
+Haskell support is available through the [Haskell extension](https://github.com/zed-extensions/haskell).
 
 - Tree-sitter: [tree-sitter-haskell](https://github.com/tree-sitter/tree-sitter-haskell)
 - Language Server: [haskell-language-server](https://github.com/haskell/haskell-language-server)