Update PULL_REQUEST_TEMPLATE.md (#6251)

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,19 +1,18 @@
 <!-- 
 Describe the changes you have made here: what, why, ... 
-Link issues by using the following pattern: #333.
-If you fixed a koppor issue, link it with following pattern: [koppor#47](https://github.com/koppor/jabref/issues/47).
+Link issues that are fixed, e.g. "Fixes #333".
+If you fixed a koppor issue, link it, e.g. "Fixes https://github.com/koppor/jabref/issues/47".
 The title of the PR must not reference an issue, because GitHub does not support autolinking there.
 -->
 
 
 <!-- 
-- All items with `[ ]` are still a TODO.
-- All items checked with `[x]` are done.
-- Remove items not applicable
+- Go through the list below. If a task has been completed, mark it done by using `[x]`.
+- Please don't remove any items, just leave them unchecked if they are not applicable.
 -->
 
 - [ ] Change in CHANGELOG.md described (if applicable)
 - [ ] Tests created for changes (if applicable)
 - [ ] Manually tested changed features in running JabRef (always required)
-- [ ] Screenshots added in PR description (for bigger UI changes)
-- [ ] [Checked documentation](https://docs.jabref.org/): Is the information available and up to date? If not: Issue created at <https://github.com/JabRef/user-documentation/issues>.
+- [ ] Screenshots added in PR description (for UI changes)
+- [ ] [Checked documentation](https://docs.jabref.org/): Is the information available and up to date? If not created an issue at <https://github.com/JabRef/user-documentation/issues> or, even better, submitted a pull request to the documentation repository.