Chapter 9 production polish (#141)

* Make warnings more specific

* Remove top imports to add them where they are used in the file instead

* Set random see to something different to show students it is not always the same number

* Make colored labels consistent in demo plot with the actual KMeans plot later

* Remove unnecessary plot config

* Match text labels with clusters

* FIx minor formatting

* Remove unnecessary printing of cluster info

* Improve explanation of cluster labels

* Change explanation of bump in elbow plot since this does not happen by default in sklearn

* Fix typo in text cluster colors

* Add automatically changed cell tag quotation

* Make standard scaler approach consistent with other chapters

* Print labels

* Note that inertia is sklearn specific

* Use list comprehension instead of for loop

* Clarify unfortunate centroid initialization

* minor polish

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Co-authored-by: Trevor Campbell <[email protected]>

Author: joelostblom