DOC: skip a doctest that writes to disk (#50454)

Author: Moisan

pandas/io/formats/style_render.py

@@ -1125,7 +1125,8 @@ def format(
 
         >>> df = pd.DataFrame({"A": [1, 0, -1]})
         >>> pseudo_css = "number-format: 0§[Red](0)§-§@;"
-        >>> df.style.applymap(lambda v: pseudo_css).to_excel("formatted_file.xlsx")
+        >>> filename = "formatted_file.xlsx"
+        >>> df.style.applymap(lambda v: pseudo_css).to_excel(filename) # doctest: +SKIP
 
         .. figure:: ../../_static/style/format_excel_css.png
         """