Fig 1.5 uses multiline expr before introduction

[trevorcampbell]

We should only use multiline stuff after 1.8 in the book

[trevorcampbell]

The relevant source file is in source/img/key_files/code-figures.pptx -- but the code is stored as a static image that isn't editable, so I can't fix this without knowing which editor the original figures were created from

[trevorcampbell]

Ah no I think they were created by rendering a code block in jupyterbook and then screenshotting it.

Unfortunately jupyterbook has changed its syntax highlighting since that first build, so we probably need to regenerate all the "syntax helper" figures

[trevorcampbell]

See also #191 for other syntax fig issue that should be closed at the same time as this one