BUG: df.insert can't accept int64 value

[auderson]

Pandas version checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pandas.

• I have confirmed this bug exists on the main branch of pandas.

Reproducible Example

import pandas as pd

df = pd.DataFrame({"a":[1,2]})
loc_a = df.columns.get_indexer(["a"])[0]
df.insert(loc_a, "b", 0)

Issue Description

the above code will output:

Traceback (most recent call last):
  File "/home/auderson/mambaforge/envs/py3.10/lib/python3.10/site-packages/IPython/core/interactiveshell.py", line 3508, in run_code
    exec(code_obj, self.user_global_ns, self.user_ns)
  File "<ipython-input-11-6dcccd9b83bc>", line 1, in <module>
    df.insert(loc_a, "b", 0)
  File "/home/auderson/mambaforge/envs/py3.10/lib/python3.10/site-packages/pandas/core/frame.py", line 4784, in insert
    raise TypeError("loc must be int")
TypeError: loc must be int

Expected Behavior

insert column correctly

Installed Versions

/home/auderson/mambaforge/envs/py3.10/lib/python3.10/site-packages/_distutils_hack/init.py:33: UserWarning: Setuptools is replacing distutils.
warnings.warn("Setuptools is replacing distutils.")

INSTALLED VERSIONS

commit : 37ea63d
python : 3.10.10.final.0
python-bits : 64
OS : Linux
OS-release : 5.15.0-71-generic
Version : #78-Ubuntu SMP Tue Apr 18 09:00:29 UTC 2023
machine : x86_64
processor : x86_64
byteorder : little
LC_ALL : None
LANG : en_US.UTF-8
LOCALE : en_US.UTF-8
pandas : 2.0.1
numpy : 1.23.5
pytz : 2023.3
dateutil : 2.8.2
setuptools : 67.7.2
pip : 23.1.2
Cython : 0.29.34
pytest : 7.3.1
hypothesis : None
sphinx : None
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : 1.0.3
psycopg2 : 2.9.3
jinja2 : None
IPython : 8.13.1
pandas_datareader: None
bs4 : None
bottleneck : None
brotli :
fastparquet : None
fsspec : None
gcsfs : None
matplotlib : 3.7.1
numba : 0.57.0
numexpr : 2.8.4
odfpy : None
openpyxl : None
pandas_gbq : None
pyarrow : 11.0.0
pyreadstat : None
pyxlsb : None
s3fs : None
scipy : 1.10.1
snappy : None
sqlalchemy : 1.4.46
tables : 3.8.0
tabulate : None
xarray : None
xlrd : None
zstandard : None
tzdata : 2023.3
qtpy : None
pyqt5 : None