gh-149930: Clarify imaplib response helper types (GH-149963)

(cherry picked from commit d2d415b)

Co-authored-by: Savage Mechanic <savagemechanic@github.com>
Co-authored-by: savagemechanic <20458938+savagemechanic@users.noreply.github.com>

Author: savagemechanic

Doc/library/imaplib.rst

@@ -135,21 +135,23 @@ The second subclass allows for connections created by a child process:
 The following utility functions are defined:
 
 
-.. function:: Internaldate2tuple(datestr)
+.. function:: Internaldate2tuple(resp)
 
-   Parse an IMAP4 ``INTERNALDATE`` string and return corresponding local
-   time.  The return value is a :class:`time.struct_time` tuple or
-   ``None`` if the string has wrong format.
+   Parse a :term:`bytes-like object` containing an IMAP4 ``INTERNALDATE``
+   response and return the corresponding local time.  The return value is a
+   :class:`time.struct_time` tuple or ``None`` if the input has wrong format.
 
 .. function:: Int2AP(num)
 
    Converts an integer into a bytes representation using characters from the set
    [``A`` .. ``P``].
 
 
-.. function:: ParseFlags(flagstr)
+.. function:: ParseFlags(resp)
 
-   Converts an IMAP4 ``FLAGS`` response to a tuple of individual flags.
+   Converts a :term:`bytes-like object` containing an IMAP4 ``FLAGS`` response
+   to a tuple of individual flags as :class:`bytes`.  The return value is an
+   empty tuple if the input has wrong format.
 
 
 .. function:: Time2Internaldate(date_time)