DOC: style fix (pandas-dev#51839)

Author: HamidrezaSK

pandas/core/generic.py

@@ -3633,9 +3633,15 @@ def to_csv(
         mode : {{'w', 'x', 'a'}}, default 'w'
             Python write mode. The available write modes are:
 
-            - 'w', opens the file for writing and truncates the file if it already exists. If the file does not exist, it creates a new file.
-            - 'x', opens the file for exclusive creation, meaning it will fail if the file already exists. If the file does not exist, it creates a new file.
-            - 'a', opens the file for writing in append mode. The data is written to the end of the file, without truncating it. If the file does not exist, it creates a new file.
+            - 'w', opens the file for writing and truncates the file if it
+              already exists. If the file does not exist, it creates a new
+              file.
+            - 'x', opens the file for exclusive creation, meaning it will fail
+              if the file already exists. If the file does not exist, it
+              creates a new file.
+            - 'a', opens the file for writing in append mode. The data is
+              written to the end of the file, without truncating it. If the
+              file does not exist, it creates a new file.
 
         encoding : str, optional
             A string representing the encoding to use in the output file,