Update description of columns parameter for read_csv to match current behaviour

[ned2]

The docs have this to say about the columns parameter for the read_csv function:

A struct that specifies the column names and column types contained within the CSV file (e.g., {'col1': 'INTEGER', 'col2': 'VARCHAR'}). Using this option implies that auto detection is not used.

Focusing on the part in bold, I noticed that the CSV sniffer is still used to infer other properties of the CSV file such as the delimiter. @pdet confirmed that this is the case, and that this call out probably used to be accurate but is no longer.

Perhaps this emboldened text could either be removed or replaced with something more accurate such as: Using this option means that auto detection is not used for inferring the schema of the results.