Pre-pdf submission fixes

[dicook]

• [x] 10-model-based table needs fixing
• [x] Add exercises to 13-Intro to supervised classification
• [x] Add risk_MSA data explanation to Appendix A
• [ ] Check and remove commented text from the qmd
• [ ] Check title consistency of references
• [ ] Check references are not duplicated
• [ ] Add single-cell example to spin-and-brush chapter, for checking validity of NLDR
• [ ] check code blocks are all ok to keep in, and not outside text width
• [ ] Check index items, perhaps add more
• [ ] Check info-boxes and insight-boxes whether they need tweaking or adding more
• [ ] Check if more than one static plot is needed

[dicook]

• [ ] Add alt-text
• [ ] Expand the glossary

[dicook]

• [ ] add old data like chocolates, spam for exercises
• [ ] at least, need some simpler classification data sets,
• [ ] perhaps some simulated to explain what non-linear or separated mean in high-d, expand the intro to classification to include multiple boundaries possibility, and maybe large p?

[dicook]

• [x] rescale is now set to be FALSE, so toolbox chapter needs changing (also code examples in tourr need changing!)

[dicook]

• [x] Check pca chapter for some messy content-hidden pieces that still have some html visible when building pdf

[dicook]

• [ ] Should we always put the code to run the tour with animate_xy, for example, wherever there is the animated gif?

[dicook]

• [x] Add a "how to cite this book" in the preface.