unicode input doesn't work

[ciaran-matthew-dunne]

in my zed config I have:

  "lsp": {
    "scls": {
      "initialization_options": {
        "max_completion_items": 6, // set max completion results len for each group: words, snippets, unicode-input
        "feature_words": true, // enable completion by word
        "feature_unicode_input": true, // enable "unicode input"
        "snippets_first": true, // completions will return before snippets by default
        "feature_snippets": true, // enable snippets
        "feature_paths": true // enable path completion
      }
    }
  }

and I have

ciaran@tarski:~/.scls/unicode-input$ cat base.toml
alpha = "α"
betta = "β"
gamma = "γ"
fire = "🔥"

but no completions for these unicode characters ever appear.

any information relating to unicode input in zed would be helpful. thanks.