update PR template to include BEP header (#1797)

.github/pull_request_template.md

@@ -2,27 +2,52 @@
 
 See the [CONTRIBUTING](https://github.com/bids-standard/bids-specification/blob/master/CONTRIBUTING.md) guide. Specifically:
 
-- Please keep the title of your Pull Request (PR) short but informative - it will
-  appear in the changelog.
+- Please keep the title of your Pull Request (PR) short but informative - it will appear in the changelog.
 - If you do **not** want a PR to appear in the changelog, it must receive the `exclude-from-changelog` label.
-- Please ensure your name is credited on our [Contributors appendix](https://github.com/bids-standard/bids-specification/blob/master/src/appendices/contributors.md).
-  To add your name, please edit our [Contributors wiki](https://github.com/bids-standard/bids-specification/wiki/Contributors) and add your name with the type of contribution.
+
+- Please ensure your name is credited
+  on our [Contributors appendix](https://github.com/bids-standard/bids-specification/blob/master/src/appendices/contributors.md).
+  To add your name, please edit our [Contributors wiki](https://github.com/bids-standard/bids-specification/wiki/Contributors)
+  and add your name with the type of contribution.
   For assistance, please tag @bids-standard/maintainers.
+
 - Use one of the following prefixes in the title of your PR:
-  - `[ENH]` - enhancement of the specification that adds a new feature or
-    support for a new data type
+  - `[ENH]` - enhancement of the specification that adds a new feature or support for a new data type
   - `[FIX]` - fix of a typo or language clarification
-  - `[INFRA]` - changes to the infrastructure automating the specification
-    release (for example building HTML docs)
+  - `[INFRA]` - changes to the infrastructure automating the specification release (for example building HTML docs)
   - `[SCHEMA]` - changes to the BIDS schema and/or related code
-  - `[MISC]` - everything else including changes to the file listing
-    contributors
-- If you are opening a PR to obtain early feedback, but the changes
-  are not ready to be merged (also known as a "Work in Progress" PR), please
-  use a [Draft PR](https://github.blog/2019-02-14-introducing-draft-pull-requests/).
-- After opening the PR, our continuous integration services will automatically check your contribution  for formatting errors and render a preview of the BIDS specification with your changes.
+  - `[MISC]` - everything else including changes to the file listing contributors
+
+- If you are opening a PR to obtain early feedback,
+  but the changes are not ready to be merged (also known as a "Work in Progress" PR),
+  please use a [Draft PR](https://github.blog/2019-02-14-introducing-draft-pull-requests/).
+
+- After opening the PR, our continuous integration services will automatically check your contribution
+  for formatting errors and render a preview of the BIDS specification with your changes.
   To see the checks and preview, scroll down and click on the `show all checks` link.
-  From the list, select the `Details` link of the `ci/circleci: build_docs artifact` check to see the preview of the BIDS specification.
-- If you are updating the schema *and* you need to subsequently make changes to the bidsschematools code (validation, tests, rendering), this means your PR probably introduces a compatibility breaking change and you should increment the minor version (the second number) in `bids-specification/src/schema/SCHEMA_VERSION`.
+  From the list:
+    - select the `Details` link of the `docs/readthedocs.org:bids-specification` check to see the HTML preview of the BIDS specification.
+    - select the `Details` link of the `Check the rendered PDF version here! ` check to see the PDF preview of the BIDS specification.
+
+- If you are updating the schema *and* you need to subsequently make changes to the bidsschematools code (validation, tests, rendering),
+  this means your PR probably introduces a compatibility breaking change
+  and you should increment the minor version (the second number) in `bids-specification/src/schema/SCHEMA_VERSION`.
+
+- If you are opening a PR for a BIDS extension proposal (BEP),
+  make sure that your top message contains the following notes
+
+> [!Note]
+>
+> **We meet regularly to discuss this BEP**
+>
+> Next meeting: **insert date** on **URL to join**
+>
+> Communication channel on github repo / matrix / slack / discord : **insert URL to join**
+>
+
+> [!Tip]
+>
+> [**HTML preview of this BEP**](insert URL to HTML preview once available)
+>
 
 --- PLEASE READ AND DELETE THE TEXT ABOVE BEFORE OPENING THE PULL REQUEST ---