[Typographical error in README.md] The word "executable" in the subtitle is duplicated

[twtwtw-gj]

In README.md, there is a odd subtitle.

Path to server executable executable
https://github.com/haskell/vscode-haskell#path-to-server-executable-executable

The word "executable" is duplicated. I think that it is a typographical error.

[jneira]

@twtwtw-gj oops, many thanks for note it 👍