DOC: Account for markdown link bug in Jupyter

Author: kernc

doc/examples/Trading with Machine Learning.ipynb

@@ -604,7 +604,7 @@
     "Let's see how our data performs modeled using a simple\n",
     "[k-nearest neighbors](https://en.wikipedia.org/wiki/K-nearest_neighbors_algorithm)\n",
     "(kNN) algorithm from the state of the art\n",
-    "[scikit-learn](scikit-learn.org)\n",
+    "[scikit-learn](https://scikit-learn.org)\n",
     "Python machine learning package.\n",
     "To avoid (or at least demonstrate)\n",
     "[overfitting](https://scikit-learn.org/stable/auto_examples/model_selection/plot_underfitting_overfitting.html),\n",
@@ -867,7 +867,7 @@
     "Despite our lousy win rate, the strategy seems profitable. Let's see how it performs under\n",
     "[walk-forward optimization](https://en.wikipedia.org/wiki/Walk_forward_optimization),\n",
     "akin to k-fold or leave-one-out\n",
-    "[cross-validation](https://en.wikipedia.org/wiki/Cross-validation_(statistics)):"
+    "[cross-validation](https://en.wikipedia.org/wiki/Cross-validation_%28statistics%29):"
    ]
   },
   {

doc/examples/Trading with Machine Learning.py

@@ -124,7 +124,7 @@ def get_clean_Xy(df):
 # Let's see how our data performs modeled using a simple
 # [k-nearest neighbors](https://en.wikipedia.org/wiki/K-nearest_neighbors_algorithm)
 # (kNN) algorithm from the state of the art
-# [scikit-learn](scikit-learn.org)
+# [scikit-learn](https://scikit-learn.org)
 # Python machine learning package.
 # To avoid (or at least demonstrate)
 # [overfitting](https://scikit-learn.org/stable/auto_examples/model_selection/plot_underfitting_overfitting.html),
@@ -227,7 +227,7 @@ def next(self):
 # Despite our lousy win rate, the strategy seems profitable. Let's see how it performs under
 # [walk-forward optimization](https://en.wikipedia.org/wiki/Walk_forward_optimization),
 # akin to k-fold or leave-one-out
-# [cross-validation](https://en.wikipedia.org/wiki/Cross-validation_(statistics)):
+# [cross-validation](https://en.wikipedia.org/wiki/Cross-validation_%28statistics%29):
 
 # +
 # %%time