DOC fix spelling in `DecisionBoundaryDisplay` docstring (#24921)
DOC fix spelling in `DecisionBoundaryDisplay` docstring (#24921)

Co-authored-by: Tim Head <e3b73ad477af74e5d71307015067c6764cb1bbab@gmail.com>
scikit-learn/scikit-learn,betatim/scikit-learn,betatim/scikit-learn,betatim/scikit-learn,scikit-learn/scikit-learn,scikit-learn/scikit-learn,scikit-learn/scikit-learn,betatim/scikit-learn