minor #11324 Added hints about receiving feedback (lsmith77)

This PR was merged into the 3.4 branch.

Discussion
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Added hints about receiving feedback

relates to symfony/diversity#23

Changes made:
* define and use the term PR rather than patch
* added hint to first check existing issues/PR
* added hints and relevant links about receiving feedback
* several other minor changes

todo:
* [x] rename file to PR.rst and add entry to the redirect map

Commits
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28e44cb Added hints about receiving feedback

Author: wouterj

_build/redirection_map

@@ -361,3 +361,4 @@
 /frontend/encore/installation-no-flex /frontend/encore/installation
 /console/logging /console
 /frontend/encore/legacy-apps /frontend/encore/legacy-applications
+/contributing/code/patches /contributing/code/pull_requests