remove broken ebm-internals reference

Author: paulbkoch

docs/interpret/ebm-internals.md

@@ -6,4 +6,3 @@ This section is divided into 3 parts that build upon each other:
 [Part 1](./ebm-internals-regression.ipynb) Covers regression for pure GAM models (no interactions).
 [Part 2](./ebm-internals-classification.ipynb) Covers binary classification with interactions, ordinals, and missing values.
 [Part 3](./ebm-internals-multiclass.ipynb) Covers multiclass, and unseen values.
-[Quantile Regression](./ebm-internals-quantile-regression.ipynb) Covers quantile regression with pinball loss and prediction intervals.