doc additions (#46194)

Co-authored-by: JHM Darbyshire (MBP) <[email protected]>

Author: attack68

pandas/io/formats/style.py

@@ -2689,6 +2689,13 @@ def hide(
 
         Notes
         -----
+        .. warning::
+           This method only works with the output methods ``to_html``, ``to_string``
+           and ``to_latex``.
+
+           Other output methods, including ``to_excel``, ignore this hiding method
+           and will display all data.
+
         This method has multiple functionality depending upon the combination
         of the ``subset``, ``level`` and ``names`` arguments (see examples). The
         ``axis`` argument is used only to control whether the method is applied to row