DOC: fix what's new alignment

Author: glouppe

doc/whats_new.rst

@@ -40,17 +40,17 @@ Enhancements
      the tree. By `Arnaud Joly`_
 
 
-    - The random forest, extra tree and decision tree estimators now has a
-      method ``decision_path`` which returns the decision path of samples in
-      the tree. By `Arnaud Joly`_
+   - The random forest, extra tree and decision tree estimators now has a
+     method ``decision_path`` which returns the decision path of samples in
+     the tree. By `Arnaud Joly`_
 
-    - A new example has been added unveling the decision tree structure.
-      By `Arnaud Joly`_
+   - A new example has been added unveling the decision tree structure.
+     By `Arnaud Joly`_
 
-    - Random forest, extra trees, decision trees and gradient boosting estimator
-      accept the parameter ``min_samples_split`` and ``min_samples_leaf``
-      provided as a percentage of the training samples. By
-      `yelite`_ and `Arnaud Joly`_
+   - Random forest, extra trees, decision trees and gradient boosting estimator
+     accept the parameter ``min_samples_split`` and ``min_samples_leaf``
+     provided as a percentage of the training samples. By
+     `yelite`_ and `Arnaud Joly`_
 
 Bug fixes
 .........