FIX use double bracket for substitution

Author: glemaitre

imblearn/ensemble/_forest.py

@@ -91,7 +91,7 @@ class BalancedRandomForestClassifier(RandomForestClassifier):
     n_estimators : int, default=100
         The number of trees in the forest.
 
-    criterion : {"gini", "entropy"}, default="gini"
+    criterion : {{"gini", "entropy"}}, default="gini"
         The function to measure the quality of a split. Supported criteria are
         "gini" for the Gini impurity and "entropy" for the information gain.
         Note: this parameter is tree-specific.

imblearn/over_sampling/_rose.py

@@ -72,15 +72,15 @@ class ROSE(BaseOverSampler):
     >>> from imblearn.over_sampling import ROSE
     >>> from sklearn.datasets import make_classification
     >>> from collections import Counter
-    >>> r = ROSE(shrink_factors={0:1, 1:0.5, 2:0.7})
+    >>> r = ROSE(shrink_factors={{0:1, 1:0.5, 2:0.7}})
     >>> X, y = make_classification(n_classes=3, class_sep=2,
     ... weights=[0.1, 0.7, 0.2], n_informative=3, n_redundant=1, flip_y=0,
     ... n_features=20, n_clusters_per_class=1, n_samples=2000, random_state=10)
     >>> print('Original dataset shape %s' % Counter(y))
-    Original dataset shape Counter({1: 1400, 2: 400, 0: 200})
+    Original dataset shape Counter({{1: 1400, 2: 400, 0: 200}})
     >>> X_res, y_res = r.fit_resample(X, y)
     >>> print('Resampled dataset shape %s' % Counter(y_res))
-    Resampled dataset shape Counter({2: 1400, 1: 1400, 0: 1400})
+    Resampled dataset shape Counter({{2: 1400, 1: 1400, 0: 1400}})
     """
 
     @_deprecate_positional_args