Remove profile CLI command parameter docstring

[mzjp2]

Resolves #1271 -- looks like this now (see issue for what it used to look like):

I apologise for the small PR, but it was bugging me 👀

[coveralls]

Coverage increased (+0.02%) to 77.759% when pulling 80f77ac on mzjp2:fix/profile-docstring into 9323f9f on great-expectations:develop.

[Aylr]

@ge-cla-bot check

[codecov]

Codecov Report

Merging #1272 into develop will not change coverage by %.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop    #1272   +/-   ##
========================================
  Coverage    77.75%   77.75%           
========================================
  Files          107      107           
  Lines        12360    12360           
========================================
  Hits          9611     9611           
  Misses        2749     2749           

Impacted Files	Coverage Δ
great_expectations/cli/datasource.py	70.76% <ø> (ø)

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[mzjp2]

Snuck in a little fix for the 0.9.8 changelog -- hope you don't mind 👀

[Aylr]

Thanks for the fixes!