[BUG] changed wrong docstring default value of start_with_window in…

… `SlidingWindowSplitter` to actual default value (#3340)

Fixes #3315.
Changes wrong docstring default value of `start_with_window` in `SlidingWindowSplitter` to actual default value.

The default value was mentioned to be False, but it should be True, in the code, it has been rightly used but, in the docstring, there was an error. Changed the default value in the docstring.

sktime/forecasting/model_selection/_split.py

@@ -1106,7 +1106,7 @@ class SlidingWindowSplitter(BaseWindowSplitter):
         Step length between windows
     initial_window : int or timedelta or pd.DateOffset, optional (default=None)
         Window length of first window
-    start_with_window : bool, optional (default=False)
+    start_with_window : bool, optional (default=True)
         - If True, starts with full window.
         - If False, starts with empty window.
 

sktime/transformations/series/boxcox.py

@@ -265,6 +265,7 @@ def _transform(self, X, y=None):
         y : ignored argument for interface compatibility
             Additional data, e.g., labels for transformation
 
+
         Returns
         -------
         Xt : 2D np.ndarray
@@ -285,6 +286,7 @@ def _inverse_transform(self, X, y=None):
         y : ignored argument for interface compatibility
             Additional data, e.g., labels for transformation
 
+
         Returns
         -------
         Xt : 2D np.ndarray