DOC Fix KernelPCA docstrings for transform functions to match PCA class docstrings. (scikit-learn#31823)

Author: MarekPokropinski

sklearn/decomposition/_kernel_pca.py

@@ -471,7 +471,7 @@ def fit_transform(self, X, y=None, **params):
         Returns
         -------
         X_new : ndarray of shape (n_samples, n_components)
-            Returns the instance itself.
+            Transformed values.
         """
         self.fit(X, **params)
 
@@ -495,7 +495,8 @@ def transform(self, X):
         Returns
         -------
         X_new : ndarray of shape (n_samples, n_components)
-            Returns the instance itself.
+            Projection of X in the first principal components, where `n_samples`
+            is the number of samples and `n_components` is the number of the components.
         """
         check_is_fitted(self)
         X = validate_data(self, X, accept_sparse="csr", reset=False)
@@ -545,7 +546,8 @@ def inverse_transform(self, X):
         Returns
         -------
         X_original : ndarray of shape (n_samples, n_features)
-            Returns the instance itself.
+            Original data, where `n_samples` is the number of samples
+            and `n_features` is the number of features.
 
         References
         ----------