[joss review] issues with documentation

[hbaniecki]

related to openjournals/joss-reviews#5873

1. Documentation https://pudu-py.github.io/pudu/definitions.html on Importance/Speed/Synergy seems sparse and has no references to relevant literature
2. Examples in documentation should show outputs of the executed code, e.g. plots, could also use more description to guide users

[enricgrau]

@hbaniecki Thank you for opening this issue. Regarding your observations:

1. We have improved the definitions section. However, as these are methodologies that we are introducing, we have struggled to add additional references to them. We hope that considering the new focus of the manuscript and library regarding spectroscopic data those definitions make more sense. Despite this, we are happy to look deeper into the matter if you believe this is paramount for the publication.
2. We now show an improved examples section adding the output images and more context to each example.

[hbaniecki]

Thanks for clarifying that this methodology is introduced here