docs: fix MethodSettings CloudFormation link

[brettstack]

Issue #, if available:

Description of changes:

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 #1027 into develop will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop    #1027   +/-   ##
========================================
  Coverage    94.81%   94.81%           
========================================
  Files           69       69           
  Lines         3240     3240           
  Branches       631      631           
========================================
  Hits          3072     3072           
  Misses          87       87           
  Partials        81       81

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