Rewrite docstrings for skll/data/readers.py

[RobertImbrie]

• Add space between parameters.
• Change ` to `` when referring to code.
• Remove 'optional' from parameters with default values.
• Move default values next to parameter names.
• Specify shape of arrays and array-likes.
• Update skll.FeatureSet and skll.Reader to skll.data.FeatureSet and skll.data.Reader
• Line up variables and text in replace_blanks_with parameter descriptions to improve legibility.

Notes: Before the pull request is approved, I'd like to note that both instances of the replace_blanks_with parameter include a 'value' option with unspecified type, shown here:

replace_blanks_with : value, ``dict``, or ``None``, default=None

Later, in the parameter description, it says that this value must be numeric:

value   = A (numeric) value with which to replace blank values.

If that's the case, shouldn't we refer to it as Number instead of 'value'?

[codecov[bot]]

Codecov Report

Merging #686 (35e3043) into main (391cf34) will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #686   +/-   ##
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  Coverage   96.85%   96.85%           
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  Files          63       63           
  Lines        9098     9098           
=======================================
  Hits         8812     8812           
  Misses        286      286           

Impacted Files	Coverage Δ
skll/data/readers.py	90.13% <ø> (ø)

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[desilinguist]

@RobertImbrie please take a look at my pushed changes and see if they make sense.

[RobertImbrie]

@desilinguist Hi! Apologies for the slow response. It does look good, with one exception! On line 754, you change

     replace_blanks_with : value, ``dict``, or ``None``, default=None

to

     replace_blanks_with : value, ``dict``, or ``None``, default=``None``

In both sklearn and the previous pushes, the default=ExampleVariable section of the parameter header typically doesn't have quotes.

On a related note, did you have any input on using 'value' vs. Number? I included a question about it in my initial comment.

[desilinguist]

@RobertImbrie good catch, please feel free to fix that quote issue. And yes, number instead of value seems like a better way to describe it! Please go ahead an make that change as well.

[RobertImbrie]

@desilinguist Changes have been pushed!