(Elixir) Apostrophe code point character literal syntax (`?'`) comments out the rest of the code

[codingthat]

Describe the issue
If you use the legitimate sequence ?' to represent the code point of the apostrophe character in Elixir code, highlight.js treats everything after the ' as a comment:

Which language seems to have the issue?

elixir

Are you using highlight or highlightAuto?

highlight

Sample Code to Reproduce

defmodule Acronym do
  defguardp apostrophe?(c) when c == ?'
  defguardp upper?(c) when (c >= ?A and c <= ?Z)
end

...as seen at https://jsfiddle.net/5gkn4hyw/

Expected behavior
The code after the ?' sequence should continue to highlight normally. (Above, GitHub gets it right.)

[codingthat]

Side note, the defguardp keyword is also missing, per the screenshot.