useMentionAutocomplete(replace: (start: number,end: number,text: string,word: boolean) => void,everyone?: boolean): UseMentionAutocompleteResult
Returns the suggestions' state and the functions that drive them. A pick
goes through replace, TextEditor's function that puts the text over
[start, end) of the textarea's value, followed by a space when word is
set. With everyone, which the chat's composer sets for a role with
chat:everyone, @everyone is offered too.