Align PR template placeholder to <package> for consistency

Author: hujc7

.github/PULL_REQUEST_TEMPLATE.md

@@ -47,7 +47,7 @@ To upload images to a PR -- simply drag and drop an image while in edit mode and
 - [ ] I have made corresponding changes to the documentation
 - [ ] My changes generate no new warnings
 - [ ] I have added tests that prove my fix is effective or that my feature works
-- [ ] I have added a changelog fragment under `source/<pkg>/changelog.d/` for every touched package (do **not** edit `CHANGELOG.rst` or bump `extension.toml` — CI handles that)
+- [ ] I have added a changelog fragment under `source/<package>/changelog.d/` for every touched package (do **not** edit `CHANGELOG.rst` or bump `extension.toml` — CI handles that)
 - [ ] I have added my name to the `CONTRIBUTORS.md` or my name already exists there
 
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