Correct a couple of unbalanced parenthesis. (GH-10779)

(cherry picked from commit 55f41e45b4318cbe19209f5144641344d0049fb8)

Co-authored-by: Andre Delfino <adelfino@gmail.com>
diff --git a/Doc/library/email.parser.rst b/Doc/library/email.parser.rst
index 49b4e99..d9a6161 100644
--- a/Doc/library/email.parser.rst
+++ b/Doc/library/email.parser.rst
@@ -164,7 +164,7 @@
       envelope header.  The header block is terminated either by the end of the
       data or by a blank line.  Following the header block is the body of the
       message (which may contain MIME-encoded subparts, including subparts
-      with a :mailheader:`Content-Transfer-Encoding` of ``8bit``.
+      with a :mailheader:`Content-Transfer-Encoding` of ``8bit``).
 
       Optional *headersonly* is a flag specifying whether to stop parsing after
       reading the headers or not.  The default is ``False``, meaning it parses