(feat): added reminder to reference related issue

gitlab/merge_request_templates/Contributor.md

 ## Community contributors
 
-Thanks for your interest in the site! To ensure your changes are merged swiftly, please make sure you have done the following before submitting your merge request:
+Thanks for your interest in the site! To ensure your changes are merged swiftly, please make sure you have done the following before submitting your merge request (MR):
 
 - Sign the [Contributor License Agreement](https://powerforms.docusign.net/e9c0907f-7056-403e-9972-0caad4ced5b6?env=na3-eu1)
 - Read the [Contributing guide](https://developers.minds.com/docs/contributing/contributing/)
 - Understand [how we use GitLab](https://developers.minds.com/docs/guides/git/)
 
-When you're ready to submit, you can delete this template (except for the labelling Quick Action shortcut below) and replace it with a detailed description of your merge request.
+When you're ready to submit, you can delete this template (except for the labelling Quick Action shortcut below) and replace it with:
+
+- A detailed description of your MR
+- A reference to the issue that will be closed when your MR is merged
 
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