bpo-33460: remove ellipsis that look like continuation prompts (GH-7851)

Remove ellipsis that look like continuation prompts,
has a side benefit of putting rest of error message in proper text color.
(cherry picked from commit f019579828)

Co-authored-by: Lew Kurtz <37632626+lew18@users.noreply.github.com>

Doc/tutorial/introduction.rst

@@ -223,10 +223,14 @@ This only works with two literals though, not with variables or expressions::
 
    >>> prefix = 'Py'
    >>> prefix 'thon'  # can't concatenate a variable and a string literal
-     ...
+     File "<stdin>", line 1
+       prefix 'thon'
+                   ^
    SyntaxError: invalid syntax
    >>> ('un' * 3) 'ium'
-     ...
+     File "<stdin>", line 1
+       ('un' * 3) 'ium'
+                      ^
    SyntaxError: invalid syntax
 
 If you want to concatenate variables or a variable and a literal, use ``+``::
@@ -320,10 +324,12 @@ Python strings cannot be changed --- they are :term:`immutable`.
 Therefore, assigning to an indexed position in the string results in an error::
 
    >>> word[0] = 'J'
-     ...
+   Traceback (most recent call last):
+     File "<stdin>", line 1, in <module>
    TypeError: 'str' object does not support item assignment
    >>> word[2:] = 'py'
-     ...
+   Traceback (most recent call last):
+     File "<stdin>", line 1, in <module>
    TypeError: 'str' object does not support item assignment
 
 If you need a different string, you should create a new one::

Misc/NEWS.d/next/Documentation/2018-06-22-08-38-29.bpo-33460.kHt4D0.rst

@@ -0,0 +1 @@
+replaced ellipsis with correct error codes in tutorial chapter 3.