Fix typo.

Doc/lib/libimaplib.tex

@@ -247,7 +247,7 @@ data = authobject(response)
   Returned data are tuples of message part envelope and data.
 \end{methoddesc}
 
-\begin{methoddes}{myrights}{mailbox}
+\begin{methoddesc}{myrights}{mailbox}
   Show my ACLs for a mailbox (i.e. the rights that I have on mailbox).
 \versionadded{2.4}
 \end{methoddesc}