Docstring of rename-buffer

[Antoine Levitt]

rename-buffer currently prompts "Rename buffer (to new name)", which
feels a bit clumsy (the parenthesis is here to dispel an ambiguity that
could be avoided in the first place). How about this?

=== modified file 'src/ChangeLog'
--- src/ChangeLog       2011-08-24 11:49:54 +0000
+++ src/ChangeLog       2011-08-24 12:41:30 +0000
@@ -1,3 +1,7 @@
+2011-08-24  Antoine Levitt  <address@hidden>
+
+       * buffer.c (Frename_buffer): Clarify prompt.
+
 2011-08-24  Eli Zaretskii  <address@hidden>
 
        * xdisp.c (Fcurrent_bidi_paragraph_direction): For unibyte

=== modified file 'src/buffer.c'
--- src/buffer.c        2011-07-28 17:46:21 +0000
+++ src/buffer.c        2011-08-24 12:30:18 +0000
@@ -1233,7 +1233,7 @@
 }
 
 DEFUN ("rename-buffer", Frename_buffer, Srename_buffer, 1, 2,
-       "(list (read-string \"Rename buffer (to new name): \" \
+       "(list (read-string (format \"Rename %s to: \" (current-buffer)) \
              nil 'buffer-name-history (buffer-name (current-buffer))) \
              current-prefix-arg)",
        doc: /* Change current buffer's name to NEWNAME (a string).