Series.append raises TypeError with tuple of Series
mypy error: 
```
pandas\core\series.py:2733:25: error: Unsupported operand types for + ("List[Any]" and "Tuple[Any, ...]")
pandas\core\series.py:2733:25: note: Right operand is of type "Union[List[Any], Tuple[Any, ...]]"
```

#### Code Sample, a copy-pastable example if possible

```python
>>> import pandas as pd
>>> pd.__version__
'0.25.0+332.g261c3a667'
>>>
>>> ser = pd.Series([1,2,3])
>>>
>>> ser
0    1
1    2
2    3
dtype: int64
>>>
>>> ser.append(ser)
0    1
1    2
2    3
0    1
1    2
2    3
dtype: int64
>>>
>>> ser.append([ser,ser])
0    1
1    2
2    3
0    1
1    2
2    3
0    1
1    2
2    3
dtype: int64
>>>
>>> ser.append((ser,ser))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Users\simon\OneDrive\code\pandas-simonjayhawkins\pandas\core\series.py", line 2733, in append
    to_concat = [self] + to_append
TypeError: can only concatenate list (not "tuple") to list

```
#### Problem description

The docstring for Series.append states `to_append : Series or list/tuple of Series`. Appending a tuple of Series raises `TypeError: can only concatenate list (not "tuple") to list`