entry for wiener diffusion model

[Franzi2114]

Summary

This PR adds a user's guide entry for the wiener diffusion model. It is linked to the PRs for the seven parameter diffusion model PDF and CDF functions
stan-dev/math#2822
stan-dev/math#3042

Copyright and Licensing

Please list the copyright holder for the work you are submitting (this will be you or your assignee, such as a university or company):

Franziska Henrich

By submitting this pull request, the copyright holder is agreeing to license the submitted work under the following licenses:

• Code: BSD 3-clause (https://opensource.org/licenses/BSD-3-Clause)
• Documentation: CC BY-ND 4.0 (https://creativecommons.org/licenses/by-nd/4.0/)

[bob-carpenter]

Thanks, so much, @Franzi2114. If nobody else can get to this, I can review it some time over the next week.

[Franzi2114]

Perfec,t thanks @bob-carpenter! I was also in contact with @WardBrian before I did the PR.

There are still three open points that I didn't manage to incorporate:

• The citations did not work locally although I added the entries in the bib file
• I would prefer to include the .pdf version instead of the .jpeg version of the image as it has much higher quality
• and there could be inserted a link to another subchapter of the User’s guide.

Please let me know when there occur more points that I should change.

[WardBrian]

Hi @Franzi2114 --

I've just pushed a commit that addresses each of your comments, since they're mostly quarto-wrangling:

• The citations issue seems to have just been a small typo.
• Quarto supports multi-format figures, so as it is currently written the website will use the JPG and the pdf manual will use the PDF. If you have a higher-quality raster image (png, nicer jpg, etc) we can use that on the web version instead
• I added the link and made sure that this new chapter shows up on the sidebar.