Fix broken link to pull request template in dev docs (#20609)
Summary of the issue:
The link "Pull Request template" in the Code Review Checklist section of projectDocs/dev/githubPullRequestTemplateExplanationAndExamples.md points to .github/PULL_REQUEST_TEMPLATE.md as a relative path. From the file's location in projectDocs/dev/, GitHub resolves it to projectDocs/dev/.github/PULL_REQUEST_TEMPLATE.md, which does not exist, resulting in a 404 when clicked.
Description of user facing changes:
N/A
Description of developer facing changes:
Developers reading the PR explanation document can now reach the pull request template from the Code Review Checklist section without hitting a broken link.
Description of development approach:
Changed the relative link from .github/PULL_REQUEST_TEMPLATE.md to ../../.github/PULL_REQUEST_TEMPLATE.md. Each ../ moves up one directory level; from projectDocs/dev/, ../../ reaches the repository root, so the link now resolves to the existing .github/PULL_REQUEST_TEMPLATE.md.
