test(project): render bash argv findings with ast.get_source_segment (#2306)

The #2306 scan test called ast.unparse, which is 3.9+, outside a version
gate, so the #1899 guard failed Project tests on every PR merged with main.
ast.get_source_segment (3.8+) renders the same finding.

Tests: test_bash_startup_files_2306 and test_ast_unparse_is_gated_1899_unit
pass (6 passed).

Author: JarryShaw

tests/project/test_bash_startup_files_2306.py

@@ -100,8 +100,10 @@ def test_no_module_spells_out_a_bash_argv(self) -> None:
         for path in sorted(TESTS.rglob('*.py')):
             if path.resolve() == pathlib.Path(__file__).resolve():
                 continue
-            tree = ast.parse(path.read_text(encoding='utf-8'), str(path))
-            found.extend(f'{path.relative_to(TESTS.parent).as_posix()}:{node.lineno}: {ast.unparse(node)}'
+            source = path.read_text(encoding='utf-8')
+            tree = ast.parse(source, str(path))
+            found.extend(f'{path.relative_to(TESTS.parent).as_posix()}:{node.lineno}: '
+                         f'{ast.get_source_segment(source, node)}'
                          for node in ast.walk(tree) if is_bash_argv(node))
         self.assertEqual(found, [], 'build these with tests._support.bash_argv')