gh-101100: Fix Sphinx warning in tutorial/introduction.rst (#111173)

Author: m-aciek

Doc/tools/.nitignore

@@ -140,7 +140,6 @@ Doc/reference/expressions.rst
 Doc/reference/import.rst
 Doc/reference/simple_stmts.rst
 Doc/tutorial/datastructures.rst
-Doc/tutorial/introduction.rst
 Doc/using/windows.rst
 Doc/whatsnew/2.0.rst
 Doc/whatsnew/2.1.rst

Doc/tutorial/introduction.rst

@@ -428,7 +428,7 @@ type, i.e. it is possible to change their content::
     [1, 8, 27, 64, 125]
 
 You can also add new items at the end of the list, by using
-the :meth:`~list.append` *method* (we will see more about methods later)::
+the :meth:`!list.append` *method* (we will see more about methods later)::
 
    >>> cubes.append(216)  # add the cube of 6
    >>> cubes.append(7 ** 3)  # and the cube of 7