BUG: to_html misses truncation indicators (...) when index=False and max_cols < len(columns)
#### Code Sample

```python
np.random.seed(seed=0)
df = pd.DataFrame(np.random.randn(2,5))
df.to_html(max_cols=4, index=False)
```

#### Problem description

similar to #15019 with `max_cols` instead of `max_rows`

#### Output

<table border="1" class="dataframe">
  <thead>
    <tr style="text-align: right;">
      <th>0</th>
      <th>1</th>
      <th>3</th>
      <th>...</th>
      <th>4</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>1.764052</td>
      <td>0.400157</td>
      <td>2.240893</td>
      <td>1.867558</td>
    </tr>
    <tr>
      <td>-0.977278</td>
      <td>0.950088</td>
      <td>-0.103219</td>
      <td>0.410599</td>
    </tr>
  </tbody>
</table>

#### Expected Output

<table border="1" class="dataframe">
  <thead>
    <tr style="text-align: right;">
      <th>0</th>
      <th>1</th>
      <th>...</th>
      <th>3</th>
      <th>4</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>1.764052</td>
      <td>0.400157</td>
      <td>...</td>
      <td>2.240893</td>
      <td>1.867558</td>
    </tr>
    <tr>
      <td>-0.977278</td>
      <td>0.950088</td>
      <td>...</td>
      <td>-0.103219</td>
      <td>0.410599</td>
    </tr>
  </tbody>
</table>

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

<details>

INSTALLED VERSIONS
------------------
commit: None
python: 3.6.5.final.0
python-bits: 64
OS: Windows
OS-release: 10
machine: AMD64
processor: Intel64 Family 6 Model 58 Stepping 9, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None

pandas: 0.23.0
pytest: 3.5.1
pip: 10.0.1
setuptools: 39.1.0
Cython: 0.28.2
numpy: 1.14.3
scipy: 1.1.0
pyarrow: None
xarray: None
IPython: 6.4.0
sphinx: 1.7.4
patsy: 0.5.0
dateutil: 2.7.3
pytz: 2018.4
blosc: None
bottleneck: 1.2.1
tables: 3.4.3
numexpr: 2.6.5
feather: None
matplotlib: 2.2.2
openpyxl: 2.5.3
xlrd: 1.1.0
xlwt: 1.3.0
xlsxwriter: 1.0.4
lxml: 4.2.1
bs4: 4.6.0
html5lib: 1.0.1
sqlalchemy: 1.2.7
pymysql: None
psycopg2: None
jinja2: 2.10
s3fs: None
fastparquet: None
pandas_gbq: None
pandas_datareader: None

</details>
