#15543: glossary entry for and 'universal newlines', and links to it.
Patch by Chris Jerdonek.
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 30ac614..4383cd4 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -859,13 +859,17 @@
binary mode, on systems that differentiate between binary and text files; on
systems that don't have this distinction, adding the ``'b'`` has no effect.
+ .. index::
+ single: universal newlines; open() built-in function
+
In addition to the standard :c:func:`fopen` values *mode* may be ``'U'`` or
- ``'rU'``. Python is usually built with universal newline support; supplying
+ ``'rU'``. Python is usually built with :term:`universal newlines` support;
+ supplying
``'U'`` opens the file as a text file, but lines may be terminated by any of the
following: the Unix end-of-line convention ``'\n'``, the Macintosh convention
``'\r'``, or the Windows convention ``'\r\n'``. All of these external
representations are seen as ``'\n'`` by the Python program. If Python is built
- without universal newline support a *mode* with ``'U'`` is the same as normal
+ without universal newlines support a *mode* with ``'U'`` is the same as normal
text mode. Note that file objects so opened also have an attribute called
:attr:`newlines` which has a value of ``None`` (if no newlines have yet been
seen), ``'\n'``, ``'\r'``, ``'\r\n'``, or a tuple containing all the newline