Rewrite docstrings for skll/config/__init__.py

[RobertImbrie]

Addresses issue #647.

• Add line of spacing between docstring parameters.
• Indicate default values after parameter type.
• Add missing period to a single parameter's description.

Note: No array parameters found in this file.

[codecov[bot]]

Codecov Report

Merging #681 (85020bc) into main (ce7516c) will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #681   +/-   ##
=======================================
  Coverage   96.85%   96.85%           
=======================================
  Files          63       63           
  Lines        9098     9098           
=======================================
  Hits         8812     8812           
  Misses        286      286           

Impacted Files	Coverage Δ
skll/config/__init__.py	95.28% <ø> (ø)

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[RobertImbrie]

@desilinguist Suggested changes have been made! Had to make a third commit to fix a typo.