- "Toggle Iswitchb global minor mode.
-With arg, turn Iswitchb mode on if ARG is positive, otherwise turn it off.
-This mode enables switching between buffers using substrings. See
-`iswitchb' for details."
+ "Toggle Iswitchb mode.
+With a prefix argument ARG, enable Iswitchb mode if ARG is
+positive, and disable it otherwise. If called from Lisp, enable
+the mode if ARG is omitted or nil.
+
+Iswitchb mode is a global minor mode that enables switching
+between buffers using substrings. See `iswitchb' for details."