docs: Update OEP-1: Rejected or withdrawn PRs may be left unmerged

Reflect reality that rejected or withdrawn proposals are frequently left
unmerged even though OEP-1 had previously called for it.

Addresses #428

oeps/processes/oep-0001.rst

@@ -326,9 +326,10 @@ the PR, and the Last-Modified header should be set to the current date.
 
 Please note that OEP statuses do not necessarily coincide with the status of
 the pull request that contains the OEP. For example, OEPs that have been
-rejected should still be merged, but should be marked with the "Rejected" status.
+rejected may still be merged, but should be marked with the "Rejected" status.
 This preserves the rationale and description of the OEP in the generated
-documentation.
+documentation. Other draft, withdrawn, or rejected proposals may simply be
+`Unpublished OEPs`_ and can be viewed in the GitHub closed pull request view.
 
 Likewise, an OEP that is in Under Review, Provisional, or Deferred statuses can
 be merged to capture a set of edits, and to make the proposal more visible to
@@ -341,7 +342,11 @@ page to keep readers up-to-date on the plan for completing and/or implementing
 the proposal. For OEPs merging with the status of Draft or Provisional,
 a Follow-up Work link is required.
 
-If an OEP has Draft or Under Review status and the PR is under review, you can either use the intended merged status (e.g. Provisional, Accepted, etc.), or you can clarify both the current and intended status using something like the following: "Under Review (=> Provisional)". Either of these options is especially useful if the merged status is not intended to be Accepted.
+If an OEP has Draft or Under Review status and the PR is under review, you can
+either use the intended merged status (e.g. Provisional, Accepted, etc.), or you
+can clarify both the current and intended status using something like the
+following: "Under Review (=> Provisional)". Either of these options is
+especially useful if the merged status is not intended to be Accepted.
 
 OEP Maintenance
 ===============
@@ -567,6 +572,12 @@ at the top of the list.
 Change History
 **************
 
+2024-07-08
+==========
+* Reflect reality that rejected or withdrawn proposals are frequently left
+  unmerged even though OEP-1 calls for it.
+* `Pull request #601 <https://github.com/openedx/open-edx-proposals/pull/601>`_
+
 2024-06-25
 ==========
 * Remove "Withdrawn" status