chore: import upstream snapshot with attribution

docs/md/how_to/javascript/deleting.md

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+# Deleting a `table()` or `view()`
+
+Unlike standard JavaScript objects, Perspective objects such as `table()` and
+`view()` store their associated data in the WebAssembly heap. Because of this,
+as well as the current lack of a hook into the JavaScript runtime's garbage
+collector from WebAssembly, the memory allocated to these Perspective objects
+does not automatically get cleaned up when the object falls out of scope.
+
+In order to prevent memory leaks and reclaim the memory associated with a
+Perspective `table()` or `view()`, you must call the `delete()` method:
+
+```javascript
+await view.delete();
+
+// This method will throw an exception if there are still `view()`s depending
+// on this `table()`!
+await table.delete();
+```
+
+Similarly, `<perspective-viewer>` Custom Elements do not delete the memory
+allocated for the UI when they are removed from the DOM.
+
+```javascript
+await viewer.delete();
+```