bpo-22702: Clarify documentation of str.join & bytes.join (GH-156)

The "iterable iterable" phrasing created confusion between the term
reference and the parameter name.

This simplifies the phrasing to just use the parameter name
without linking directly to the term definition.

Doc/library/stdtypes.rst

@@ -1719,10 +1719,10 @@ expression support in the :mod:`re` module).
 
 .. method:: str.join(iterable)
 
-   Return a string which is the concatenation of the strings in the
-   :term:`iterable` *iterable*.  A :exc:`TypeError` will be raised if there are
-   any non-string values in *iterable*, including :class:`bytes` objects.  The
-   separator between elements is the string providing this method.
+   Return a string which is the concatenation of the strings in *iterable*.
+   A :exc:`TypeError` will be raised if there are any non-string values in
+   *iterable*, including :class:`bytes` objects.  The separator between
+   elements is the string providing this method.
 
 
 .. method:: str.ljust(width[, fillchar])
@@ -2554,11 +2554,11 @@ arbitrary binary data.
             bytearray.join(iterable)
 
    Return a bytes or bytearray object which is the concatenation of the
-   binary data sequences in the :term:`iterable` *iterable*.  A
-   :exc:`TypeError` will be raised if there are any values in *iterable*
-   that are not :term:`bytes-like objects <bytes-like object>`, including
-   :class:`str` objects.  The separator between elements is the contents
-   of the bytes or bytearray object providing this method.
+   binary data sequences in *iterable*.  A :exc:`TypeError` will be raised
+   if there are any values in *iterable* that are not :term:`bytes-like
+   objects <bytes-like object>`, including :class:`str` objects.  The
+   separator between elements is the contents of the bytes or
+   bytearray object providing this method.
 
 
 .. staticmethod:: bytes.maketrans(from, to)