fix of typo (scikit-learn#7137)

Author: JulianKahnert

doc/modules/preprocessing.rst

@@ -30,7 +30,7 @@ a learning algorithm (such as the RBF kernel of Support Vector
 Machines or the l1 and l2 regularizers of linear models) assume that
 all features are centered around zero and have variance in the same
 order. If a feature has a variance that is orders of magnitude larger
-that others, it might dominate the objective function and make the
+than others, it might dominate the objective function and make the
 estimator unable to learn from other features correctly as expected.