#11684: Complete parser bytes interface by adding BytesHeaderParser

Patch by Steffen Daode Nurpmeso.
diff --git a/Doc/library/email.parser.rst b/Doc/library/email.parser.rst
index 8da0d74..c72d3d4 100644
--- a/Doc/library/email.parser.rst
+++ b/Doc/library/email.parser.rst
@@ -94,12 +94,14 @@
 The :class:`Parser` class, imported from the :mod:`email.parser` module,
 provides an API that can be used to parse a message when the complete contents
 of the message are available in a string or file.  The :mod:`email.parser`
-module also provides a second class, called :class:`HeaderParser` which can be
-used if you're only interested in the headers of the message.
-:class:`HeaderParser` can be much faster in these situations, since it does not
-attempt to parse the message body, instead setting the payload to the raw body
-as a string. :class:`HeaderParser` has the same API as the :class:`Parser`
-class.
+module also provides header-only parsers, called :class:`HeaderParser` and
+:class:`BytesHeaderParser`, which can be used if you're only interested in the
+headers of the message.  :class:`HeaderParser` and :class:`BytesHeaderParser`
+can be much faster in these situations, since they do not attempt to parse the
+message body, instead setting the payload to the raw body as a string.  They
+have the same API as the :class:`Parser` and :class:`BytesParser` classes.
+
+.. versionadded:: 3.3 BytesHeaderParser
 
 
 .. class:: Parser(_class=email.message.Message)