Doc fix for eval-expression

* simple.el (eval-expression): Note what it does if called
interactively.

Fixes: debbugs:6495

lisp/ChangeLog

+2011-07-13  Lars Magne Ingebrigtsen  <larsi@gnus.org>
+
+	* simple.el (eval-expression): Note what it does if called
+	interactively (bug#6495).
+
 2011-07-13  Chong Yidong  <cyd@stupidchicken.com>
 
 	* window.el (switch-to-buffer): New arg FORCE-SAME-WINDOW.  Use

lisp/simple.el

@@ -1152,6 +1152,8 @@ display the result of expression evaluation."
 (defun eval-expression (eval-expression-arg
 			&optional eval-expression-insert-value)
   "Evaluate EVAL-EXPRESSION-ARG and print value in the echo area.
+When called interactively, read an Emacs Lisp expression and
+evaluate it.
 Value is also consed on to front of the variable `values'.
 Optional argument EVAL-EXPRESSION-INSERT-VALUE non-nil (interactively,
 with prefix argument) means insert the result into the current buffer