Fixed MathJax support, I'm definitely sure I had tested it at some point, but it seems that it was broken due to several factors!

MathJax/config/default.js

@@ -341,7 +341,7 @@ MathJax.Hub.Config({
     //  restart processing within an element that has been marked as
     //  ignored above.
     //
-    processClass: "texMath" //"tex2jax_process",
+    processClass: "texMath", //"tex2jax_process",
     
     //
     //  Set to "true" to allow \$ to produce a dollar without starting in-line

dollar.rkt

@@ -216,15 +216,17 @@ EOTEX
   (void))
 
 (define ($ s . strs)
+  (let ([$- ($-html-handler)])
     (cond-element
-   [html (($-html-handler) `(,s . ,strs))]
+     [html ($- `(,s . ,strs))]
      [latex `("$" ,s ,@strs "$")]
      ;; TODO: use a unicode representation of math, e.g. x^2 becomes x²
-   [else `(,s . ,strs)]))
+     [else `(,s . ,strs)])))
 
 (define ($$ s . strs)
+  (let ([$$- ($$-html-handler)])
     (cond-element
-   [html (($$-html-handler) `(,s . ,strs))]
+     [html ($$- `(,s . ,strs))]
      [latex `("\\[" ,s ,@strs "\\]")]
      ;; TODO: use a spatial representation of display math, e.g.
      ;; \sum_{i=0}^n x_i^2
@@ -240,4 +242,4 @@ EOTEX
      ;;  n
      ;;  ∑  xᵢ²
      ;; i=0
-   [else `(,s . ,strs)]))
+     [else `(,s . ,strs)])))

katex-convert-unicode.rkt

@@ -91,5 +91,9 @@
          [∀ "\\forall"]
          [∃ "\\exists"]
          [≡ "\\equiv"]
-         [≢ "\not\\equiv"]))
+         [≢ "\not\\equiv"]
+         [… "\\ldots"]
+         [⋯ "\\cdots"]
+         [⋰ "\\uddots"] ;; or \iddots from package mathdots, see http://tex.stackexchange.com/a/17650
+         [⋱ "\\ddots"]))
       str))

scribblings/scribble-math.scrbl

@@ -26,8 +26,8 @@
 
 @title[#:style (with-html5 manual-doc-style)]{@racketmodname[scribble-math]}
 @author[
- @author+email["Georges Dupéron" "georges.duperon@gmail.com"]
- @author+email["Jens Axel Søgaard" "jensaxel@soegaard.net"]]
+ @author+email["Jens Axel Søgaard" "jensaxel@soegaard.net"]
+ @author+email["Georges Dupéron" "georges.duperon@gmail.com"]]
 
 @defmodule[scribble-math]