emacs-27 7355209: * lisp/window.el (recenter-top-bottom): Clarify doc string.

[Eli Zaretskii]

branch: emacs-27
commit 7355209f53e1c7f383a1df8b5e294ec9f43ab82e
Author: Eli Zaretskii <eliz@gnu.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    * lisp/window.el (recenter-top-bottom): Clarify doc string.
---
 lisp/window.el | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/lisp/window.el b/lisp/window.el
index f388f86..95db01b 100644
--- a/lisp/window.el
+++ b/lisp/window.el
@@ -9545,13 +9545,16 @@ cycling order is middle -> top -> bottom."
   :group 'windows)
 
 (defun recenter-top-bottom (&optional arg)
-  "Move current buffer line to the specified window line.
-With no prefix argument, successive calls place point according
-to the cycling order defined by `recenter-positions'.
-
-A prefix argument is handled like `recenter':
- With numeric prefix ARG, move current line to window-line ARG.
- With plain `C-u', move current line to window center."
+  "Scroll the window so that current line is in the middle of the window.
+Successive invocations scroll the window in a cyclical order to put
+the current line at certain places within the window, as determined by
+`recenter-positions'.  By default, the second invocation puts the
+current line at the top-most window line, the third invocation puts it
+on the bottom-most window line, and then the order is reused in a
+cyclical manner.
+
+With numeric prefix ARG, move current line ARG lines below the window top.
+With plain \\[universal-argument], move current line to window center."
   (interactive "P")
   (cond
    (arg (recenter arg t))                 ; Always respect ARG.