text: Title: An Error is emitted when the ‘count’field is present in DataFrame
  Body: **Describe the bug**
  
  1.When I load a local file with a count field, it looks like this:
  
  ![image](https://user-images.githubusercontent.com/39480659/110434491-d8086c80-80ec-11eb-9b4a-57963df424b6.png)
  
  2. So I'm going to go ahead and execute, I met this error:
  'cannot insert count, already exists'
  
  its all:
  `---------------------------------------------------------------------------
  ValueError                                Traceback (most recent call last)
  ~/anaconda3/lib/python3.7/site-packages/IPython/core/formatters.py in __call__(self, obj)
      343             method = get_real_method(obj, self.print_method)
      344             if method is not None:
  --> 345                 return method()
      346             return None
      347         else:
  
  ~/anaconda3/lib/python3.7/site-packages/pandas_profiling/profile_report.py in _repr_html_(self)
      434     def _repr_html_(self):
      435         """The ipython notebook widgets user interface gets called by the jupyter notebook."""
  --> 436         self.to_notebook_iframe()
      437 
      438     def __repr__(self):
  
  ~/anaconda3/lib/python3.7/site-packages/pandas_profiling/profile_report.py in to_notebook_iframe(self)
      414         with warnings.catch_warnings():
      415             warnings.simplefilter("ignore")
  --> 416             display(get_notebook_iframe(self))
      417 
      418     def to_widgets(self):
  
  ~/anaconda3/lib/python3.7/site-packages/pandas_profiling/report/presentation/flavours/widget/notebook.py in get_notebook_iframe(profile)
       63         output = get_notebook_iframe_src(profile)
       64     elif attribute == "srcdoc":
  ---> 65         output = get_notebook_iframe_srcdoc(profile)
       66     else:
       67         raise ValueError(
  
  ~/anaconda3/lib/python3.7/site-packages/pandas_profiling/report/presentation/flavours/widget/notebook.py in get_notebook_iframe_srcdoc(profile)
       21     width = config["notebook"]["iframe"]["width"].get(str)
       22     height = config["notebook"]["iframe"]["height"].get(str)
  ---> 23     src = html.escape(profile.to_html())
       24 
       25     iframe = f'<iframe width="{width}" height="{height}" srcdoc="{src}" frameborder="0" allowfullscreen></iframe>'
  
  ~/anaconda3/lib/python3.7/site-packages/pandas_profiling/profile_report.py in to_html(self)
      384 
      385         """
  --> 386         return self.html
      387 
      388     def to_json(self) -> str:
  
  ~/anaconda3/lib/python3.7/site-packages/pandas_profiling/profile_report.py in html(self)
      199     def html(self):
      200         if self._html is None:
  --> 201             self._html = self._render_html()
      202         return self._html
      203 
  
  ~/anaconda3/lib/python3.7/site-packages/pandas_profiling/profile_report.py in _render_html(self)
      306         from pandas_profiling.report.presentation.flavours import HTMLReport
      307 
  --> 308         report = self.report
      309 
      310         disable_progress_bar = not config["progress_bar"].get(bool)
  
  ~/anaconda3/lib/python3.7/site-packages/pandas_profiling/profile_report.py in report(self)
      193     def report(self):
      194         if self._report is None:
  --> 195             self._report = get_report_structure(self.description_set)
      196         return self._report
      197 
  
  ~/anaconda3/lib/python3.7/site-packages/pandas_profiling/profile_report.py in description_set(self)
      173         if self._description_set is None:
      174             self._description_set = describe_df(
  --> 175                 self.title, self.df, self.summarizer, self.typeset, self._sample
      176             )
      177         return self._description_set
  
  ~/anaconda3/lib/python3.7/site-packages/pandas_profiling/model/describe.py in describe(title, df, summarizer, typeset, sample)
      135         # Duplicates
      136         pbar.set_postfix_str("Locating duplicates")
  --> 137         duplicates = get_duplicates(df, supported_columns)
      138         pbar.update()
      139 
  
  ~/anaconda3/lib/python3.7/site-packages/pandas_profiling/model/duplicates.py in get_duplicates(df, supported_columns)
       23             .groupby(supported_columns)
       24             .size()
  ---> 25             .reset_index(name="count")
       26             .nlargest(n_head, "count")
       27         )
  
  ~/anaconda3/lib/python3.7/site-packages/pandas/core/series.py in reset_index(self, level, drop, name, inplace)
     1247         else:
     1248             df = self.to_frame(name)
  -> 1249             return df.reset_index(level=level, drop=drop)
     1250 
     1251     # ----------------------------------------------------------------------
  
  ~/anaconda3/lib/python3.7/site-packages/pandas/core/frame.py in reset_index(self, level, drop, inplace, col_level, col_fill)
     5011                 # to ndarray and maybe infer different dtype
     5012                 level_values = maybe_casted_values(lev, lab)
  -> 5013                 new_obj.insert(0, name, level_values)
     5014 
     5015         new_obj.index = new_index
  
  ~/anaconda3/lib/python3.7/site-packages/pandas/core/frame.py in insert(self, loc, column, value, allow_duplicates)
     3758         self._ensure_valid_index(value)
     3759         value = self._sanitize_column(column, value, broadcast=False)
  -> 3760         self._mgr.insert(loc, column, value, allow_duplicates=allow_duplicates)
     3761 
     3762     def assign(self, **kwargs) -> DataFrame:
  
  ~/anaconda3/lib/python3.7/site-packages/pandas/core/internals/managers.py in insert(self, loc, item, value, allow_duplicates)
     1189         if not allow_duplicates and item in self.items:
     1190             # Should this be a different kind of error??
  -> 1191             raise ValueError(f"cannot insert {item}, already exists")
     1192 
     1193         if not isinstance(loc, int):
  
  ValueError: cannot insert count, already exists`
  
  
  3. I removed the 'count' field in train_df as if there was a conflict between my original field and the subsequent naming
  4. It seems to have worked
  
  ![image](https://user-images.githubusercontent.com/39480659/110435223-b491f180-80ed-11eb-8d48-735b05f85359.png)
  
  
  
  
  