- "Global minor mode to highlight the line about point in the current window.
-With ARG, turn Global-Hl-Line mode on if ARG is positive, off otherwise.
+ "Toggle line highlighting in all buffers (Global Hl-Line mode).
+With a prefix argument ARG, enable Global Hl-Line mode if ARG is
+positive, and disable it otherwise. If called from Lisp, enable
+the mode if ARG is omitted or nil.
+
+If `global-hl-line-sticky-flag' is non-nil, Global Hl-Line mode
+highlights the line about the current buffer's point in all
+windows.