gh-106922: Support multi-line error locations in traceback

Lib/test/test_contextlib.py

@@ -802,11 +802,17 @@ def raise_exc(exc):
         self.assertIsInstance(exc, ValueError)
         ve_frames = traceback.extract_tb(exc.__traceback__)
         expected = \
-            [('test_exit_exception_traceback', 'with self.exit_stack() as stack:')] + \
+            [(
+                'test_exit_exception_traceback',
+                'with self.exit_stack() as stack:\n'
+                '    stack.callback(raise_exc, ValueError)\n'
+                '    1/0'
+            )] + \
             self.callback_error_internal_frames + \
             [('_exit_wrapper', 'callback(*args, **kwds)'),
              ('raise_exc', 'raise exc')]
 
+        # breakpoint()
         self.assertEqual(
             [(f.name, f.line) for f in ve_frames], expected)
 

Lib/test/test_doctest.py

@@ -2918,6 +2918,9 @@ def test_unicode(): """
         Traceback (most recent call last):
           File ...
             exec(compile(example.source, filename, "single",
+            ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+                         compileflags, True), test.globs)
+                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
           File "<doctest foo-bär@baz[0]>", line 1, in <module>
             raise Exception('clé')
         Exception: clé

Lib/test/test_exceptions.py

@@ -2045,14 +2045,15 @@ def test_multiline_not_highlighted(self):
              """,
                 [
                     '    1 < 2 and',
+                    '    3 > 4',
                     'AssertionError',
                 ],
             ),
         ]
         for source, expected in cases:
             with self.subTest(source):
                 result = self.write_source(source)
-                self.assertEqual(result[-2:], expected)
+                self.assertEqual(result[-len(expected):], expected)
 
 
 class SyntaxErrorTests(unittest.TestCase):