Neal's funnel figure removed from new documentation, but referenced in the text

[TeemuSailynoja]

Summary:

This chapter references the funnel: https://mc-stan.org/docs/stan-users-guide/regression.html#boundary-avoiding-priors-for-mle-in-hierarchical-models

The link only takes the reader to the top of the page.

[TeemuSailynoja]

Here are the qmd lines in question:

docs/src/stan-users-guide/regression.qmd

Lines 874 to 879 in f71b7c7

	In this case, as $\tau \rightarrow 0$ and $\beta_k \rightarrow 0$, the
	posterior density
	$$ p(\beta,\tau,\sigma|y,x) \propto p(y|x,\beta,\tau,\sigma) $$
	grows without bound. See the [plot of Neal's funnel density](#funnel.figure), which has similar behavior.

[TeemuSailynoja]

There are still two figures of the funnel:

• Funnel samples
• Funnel density

These are used in the old documentation:

[bob-carpenter]

Thanks for the report, @TeemuSailynoja---@mitzimorris can probably sort this out as she's been reorganizing a lot of the doc.

[mitzimorris]

will investigate.