Report syntax errors as unhandled exceptions

Update tests accordingly

qutebrowser/config/configfiles.py

@@ -419,7 +419,7 @@ def read_config_py(filename, raising=False):
         desc = configexc.ConfigErrorDesc("Error while compiling", e)
         raise configexc.ConfigFileErrors(basename, [desc])
     except SyntaxError as e:
-        desc = configexc.ConfigErrorDesc("Syntax Error", e,
+        desc = configexc.ConfigErrorDesc("Unhandled exception", e,
                                          traceback=traceback.format_exc())
         raise configexc.ConfigFileErrors(basename, [desc])
 

tests/unit/config/test_configfiles.py

@@ -550,7 +550,7 @@ class TestConfigPy:
         assert len(excinfo.value.errors) == 1
         error = excinfo.value.errors[0]
         assert isinstance(error.exception, SyntaxError)
-        assert error.text == "Syntax Error"
+        assert error.text == "Unhandled exception"
         exception_text = 'invalid syntax (config.py, line 1)'
         assert str(error.exception) == exception_text