revise doc item

Author: laurenyu

.github/PULL_REQUEST_TEMPLATE.md

@@ -13,6 +13,6 @@ _Put an `x` in the boxes that apply. You can also fill these out after creating
 - [ ] I have used the regional endpoint when creating S3 and/or STS clients (if appropriate)
 - [ ] I have added tests that prove my fix is effective or that my feature works (if appropriate)
 - [ ] I have checked that my tests are not configured for a specific region or account (if appropriate)
-- [ ] I have updated any necessary [documentation](https://github.com/aws/sagemaker-python-sdk/blob/master/README.rst) (if appropriate)
+- [ ] I have updated any necessary documentation, including [READMEs](https://github.com/aws/sagemaker-python-sdk/blob/master/README.rst) and [API docs](https://github.com/aws/sagemaker-python-sdk/tree/master/doc) (if appropriate)
 
 By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.