docs: clarify empty patches array behavior (#610)

Co-authored-by: Ven <vendicated@riseup.net>

docs/2_PLUGINS.md

@@ -26,6 +26,10 @@ export default definePlugin({
             name: "Your Name",
         },
     ],
+    // Delete `patches` if you are not using code patches, as it will make
+    // your plugin require restarts, and your stop() method will not be
+    // invoked at all.  The presence of the key in the object alone is
+    // enough to trigger this behavior, even if the value is an empty array.
     patches: [],
     // Delete these two below if you are only using code patches
     start() {},