Unused prompter source slots

[jmercouris]

The following slots were removed from prompter-source, they may be useful in the future.

   (multiline nil                     ; TODO: Unused?
              :type (or boolean integer)
              :documentation
              "If non-nil, each candidate can span over multiple lines.
If an integer, it specifies the maximum number of lines allow per candidate.")

   (requires-pattern 0                ; TODO: Use!
                     :documentation
                     "Compute and display suggestions only if the pattern has
at least this number of characters.  When 0, always compute and display
suggestions.")

    (suggestion-limit 0       ; TODO: Implement.  Move to Nyxt's prompt-buffer?
                      :documentation
                      "Don't display more suggestions than this.
 If 0, there is no limit.")

[aadcg]

Do we still need this issue? @Ambrevar @jmercouris

[Ambrevar]

Yup, these are nice features that I'd like to implement when I get back to hacking on the prompter.
Unless someone beats me to it.

Note: John removed the slots in commit 4a94f9202606a9eff32e512ee3b5a848e30d003e.