DOC Fix text data tutorial (#6923)

 - Fix a typo.
 - Fix a floating point error in doctests.
 - Fix `VisibleDepricationWarning` due to conversion of an array with
   ndim > 0 to an index.
 - Convert `print` to `log` to avoid doctests failure.

Fixes: #6927

Signed-off-by: Rohan Jain <crodjer@gmail.com>