Definitions survive being deleted until reload

[Blaisorblade]

To reproduce, write in a post something with a definition, for instance:
$$\DeclareMathOperator{lim}{notLim} \lim_{z \to -\infty}z^2+a\times b+c.$$
Then, edit the post and remove the definition:
$$\lim_{z \to -\infty}z^2+a\times b+c.$$
The definition will still be active — concretely, \lim will still be rendered as notLim.

After reloading the page from scratch, the definition is not persisted.

This suggests that definition are persisted by MathJax in internal mutable state, and that different calls happen without resetting that state. I expect that state should be reset at least between the topic and the post being edited (that is, between different calls to decorateCooked's callback) — ideally, between different posts.

Important caveat: I've tested this with Discourse 1.5 and #32; that #32 is not at fault is only an educated guess.