Fix docs nits

Author: encukou

Doc/library/mailbox.rst

@@ -78,10 +78,10 @@ Supported mailbox formats are Maildir, mbox, MH, Babyl, and MMDF.
       message.  Failing to lock the mailbox runs the risk of losing messages or
       corrupting the entire mailbox.
 
-   The :class:`Mailbox` class supports the :keyword:`with` statement.  When used
-	as a context manager, :class:`!Mailbox` calls :meth:`lock` when the context is entered,
-	returns the mailbox object as the context object, and at context end calls :meth:`close`,
-	thereby releasing the lock.
+   The :class:`!Mailbox` class supports the :keyword:`with` statement.  When used
+   as a context manager, :class:`!Mailbox` calls :meth:`lock` when the context is entered,
+   returns the mailbox object as the context object, and at context end calls :meth:`close`,
+   thereby releasing the lock.
 
    .. versionchanged:: next
       Support for the :keyword:`with` statement was added.

Misc/NEWS.d/next/Library/2017-12-15-09-32-57.bpo-32234.XaOkhR.rst

@@ -1 +1,2 @@
-:mod:`Mailbox` instances can now be used as a context manager. The Mailbox is locked on context entry and unlocked and closed at context exit.
+:class:`mailbox.Mailbox` instances can now be used as a context manager.
+The Mailbox is locked on context entry and unlocked and closed at context exit.