completion usability with haskell keywords

[alanz]

Scenario: I have decided to add a where clause

Actions

• type where
• hit enter.

Instead of going to the next line and letting me continue, I get whatever the top completion suggestion is based on that prefix.

Ditto with let.

Using emacs with lsp-mode and company.

We should disable completions when fully recognising a keyword.

See also #953

[asadoll]

I use this workaround in spacemacs:

(auto-completion :variables
                   auto-completion-enable-snippets-in-popup t
                   auto-completion-enable-sort-by-usage t
                   auto-completion-tab-key-behavior 'complete  ;; complete with TAB
                   auto-completion-return-key-behavior nil     ;; disable RET
                   auto-completion-enable-help-tooltip t
                   auto-completion-use-company-box t
                 :disabled-for org erc)