org-remember.el: fix docstring, replacing %:author by %:fromname.

lisp/org-remember.el

@@ -157,7 +157,7 @@ Furthermore, the following %-escapes will be replaced with content:
 Apart from these general escapes, you can access information specific to the
 link type that is created.  For example, calling `remember' in emails or gnus
 will record the author and the subject of the message, which you can access
-with %:author and %:subject, respectively.  Here is a complete list of what
+with %:fromname and %:subject, respectively.  Here is a complete list of what
 is recorded for each link type.
 
 Link type          |  Available information