DataFrame.query() resets the column names.

[sanchaz]

Describe the bug
DataFrame.query() by string resets the columns to 0, 1, 2, ...
https://danfo.jsdata.org/api-reference/dataframe/danfo.dataframe.query#query-by-a-string-column-in-a-dataframe
According to the docs the columns should remain there.

To Reproduce
https://danfo.jsdata.org/api-reference/dataframe/danfo.dataframe.query#query-by-a-string-column-in-a-dataframe
Copy the example posted and run it.

However if you use inplace: true then the behaviour is correct.
Seems the issue is that when returning a new df it forgets to copy the columns.

Expected behavior
Column names should remain the same.

Screenshots
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Desktop (please complete the following information):

• OS: Ubuntu 20.04
• Browser Firefox
• Version 93.0 (64-bit)

Additional context
Add any other context about the problem here.

[risenW]

FIXED!