.replace() raises when replacing strings
#### Code Sample, a copy-pastable example if possible

```python
pd.Series(['a', 'b', 'c']).replace('a', 'x')
```
#### Problem description

This raises the following error:

> TypeError: Type aliases cannot be used with isinstance().

This behavior is exclusive to the new **version 0.23**. Previous versions work as expected.

Full traceback
```
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-75-761515b509b4> in <module>()
----> 1 pd.Series(['a','b','c']).replace('a', 'x')

~/.virtualenvs/new/lib/python3.5/site-packages/pandas/core/series.py in replace(self, to_replace, value, inplace, limit, regex, method)
   3427         return super(Series, self).replace(to_replace=to_replace, value=value,
   3428                                            inplace=inplace, limit=limit,
-> 3429                                            regex=regex, method=method)
   3430
   3431     @Appender(generic._shared_docs['shift'] % _shared_doc_kwargs)

~/.virtualenvs/new/lib/python3.5/site-packages/pandas/core/generic.py in replace(self, to_replace, value, inplace, limit, regex, method)
   5877                     new_data = self._data.replace(to_replace=to_replace,
   5878                                                   value=value, inplace=inplace,
-> 5879                                                   regex=regex)
   5880                 else:
   5881                     msg = ('Invalid "to_replace" type: '

~/.virtualenvs/new/lib/python3.5/site-packages/pandas/core/internals.py in replace(self, **kwargs)
   3718
   3719     def replace(self, **kwargs):
-> 3720         return self.apply('replace', **kwargs)
   3721
   3722     def replace_list(self, src_list, dest_list, inplace=False, regex=False,

~/.virtualenvs/new/lib/python3.5/site-packages/pandas/core/internals.py in apply(self, f, axes, filter, do_integrity_check, consolidate, **kwargs)
   3579
   3580             kwargs['mgr'] = self
-> 3581             applied = getattr(b, f)(**kwargs)
   3582             result_blocks = _extend_blocks(applied, result_blocks)
   3583

~/.virtualenvs/new/lib/python3.5/site-packages/pandas/core/internals.py in replace(self, to_replace, value, inplace, filter, regex, convert, mgr)
   2430         blocks = [self]
   2431
-> 2432         if not either_list and is_re(to_replace):
   2433             return self._replace_single(to_replace, value, inplace=inplace,
   2434                                         filter=filter, regex=True,

~/.virtualenvs/new/lib/python3.5/site-packages/pandas/core/dtypes/inference.py in is_re(obj)
    217     """
    218
--> 219     return isinstance(obj, re_type)
    220
    221

/usr/lib/python3.5/typing.py in __instancecheck__(self, obj)
    256
    257     def __instancecheck__(self, obj):
--> 258         raise TypeError("Type aliases cannot be used with isinstance().")
    259
    260     def __subclasscheck__(self, cls):

TypeError: Type aliases cannot be used with isinstance().
```

#### Expected Output

```
0    x
1    b
2    c
dtype: object
```

#### Output of ``pd.show_versions()``

<details>

INSTALLED VERSIONS
------------------
commit: None
python: 3.5.1.final.0
python-bits: 64
OS: Linux
OS-release: 4.13.13-5-pve
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: en_US.UTF-8
LANG: en_US.UTF-8
LOCALE: en_US.UTF-8

pandas: 0.23.0
pytest: None
pip: 8.1.1
setuptools: 20.7.0
Cython: None
numpy: 1.14.3
scipy: 1.1.0
pyarrow: None
xarray: None
IPython: 6.4.0
sphinx: None
patsy: None
dateutil: 2.6.1
pytz: 2018.4
blosc: None
bottleneck: None
tables: None
numexpr: None
feather: None
matplotlib: 2.2.2
openpyxl: None
xlrd: None
xlwt: None
xlsxwriter: None
lxml: None
bs4: None
html5lib: 0.999
sqlalchemy: None
pymysql: None
psycopg2: None
jinja2: 2.10
s3fs: None
fastparquet: None
pandas_gbq: None
pandas_datareader: None

</details>