Doc: use "unnumbered" footnotes (GH-98954)

Use unnumbered footnote in this file to avoid reseting the footnotes numbering.

Example: when building the tutorial into a PDF and using `latex_show_urls = "footnotes"`; this footnote become the number 8. However, without this change, the footnote shows the number 1.
(cherry picked from commit f042646595d1cdd2ecdc15222b1766f746d010f0)

Co-authored-by: Manuel Kaufmann <humitos@gmail.com>

diff --git a/Doc/tutorial/datastructures.rst b/Doc/tutorial/datastructures.rst
index 12b00be3793e14889d38fc9607d1ac9ac9a90386..c8e89d9b79bdddc8c0e8da89382670c28f159320 100644 (file)
--- a/Doc/tutorial/datastructures.rst
+++ b/Doc/tutorial/datastructures.rst
@@ -122,7 +122,7 @@ An example that uses most of the list methods::
 
 You might have noticed that methods like ``insert``, ``remove`` or ``sort`` that
 only modify the list have no return value printed -- they return the default
-``None``. [1]_  This is a design principle for all mutable data structures in
+``None``. [#]_  This is a design principle for all mutable data structures in
 Python.
 
 Another thing you might notice is that not all data can be sorted or
@@ -731,5 +731,5 @@ interpreter will raise a :exc:`TypeError` exception.
 
 .. rubric:: Footnotes
 
-.. [1] Other languages may return the mutated object, which allows method
+.. [#] Other languages may return the mutated object, which allows method
        chaining, such as ``d->insert("a")->remove("b")->sort();``.