Prettify document

[limitusus]

Issue #, if available:

N/A

Description of changes:

Fix rst markup, as Cognito is not been seen in TOC

Description of how you validated changes:

Checklist:

• Write/update tests
• make pr passes
• Update documentation
• Verify transformed template deploys and application functions as expected
• Add/update example to examples/2016-10-31

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov-io]

Codecov Report

Merging #1247 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1247   +/-   ##
=======================================
  Coverage   94.41%   94.41%           
=======================================
  Files          71       71           
  Lines        3619     3619           
  Branches      714      714           
=======================================
  Hits         3417     3417           
  Misses        103      103           
  Partials       99       99

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[keetonian]

@limitusus thank you for the contribution!