minor KnpLabs#878 [Documentation] Include links to Pull Request Children on Pull Request Doc. (jimlind)

This PR was merged into the 2.15.x-dev branch.

Discussion
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Commits
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5c68ecc Include links to all children

Author: acrobat

doc/pull_requests.md

@@ -3,6 +3,8 @@
 
 Additional APIs:
 * [Review Comments](pull_request/comments.md)
+* [Review Request](pull_request/review_request.md)
+* [Reviews](pull_request/reviews.md)
 
 Lets you list pull requests for a given repository, list one pull request in particular along
 with its discussion, and create a pull-request.