docs: historical posts sometimes but only best effort

templates/docs.html

@@ -272,7 +272,8 @@
 
 <li id="posts-forward" class="question">I see my profile, but I don't see my posts!</li>
 <li class="answer">
-<p>Bridgy Fed only bridges new posts going forward, not historical posts. Try a new post!</p>
+<p>Bridgy Fed sometimes bridges historical posts when you first bridge your account, but only best effort, and only on some networks. For example, it generally bridges a few historical posts from Bluesky, but not from the fediverse.</p>
+<p>It tries to bridge all posts going forward, though. Try a new post!</p>
 </li>