Don't stabilize the scroll position when the browser supports scroll …

…anchoring

FIX: ProseMirror will no longer try to stabilize the scroll position
during updates on browsers that support [scroll
anchoring](https://developer.mozilla.org/en-US/docs/Web/CSS/overflow-anchor),
since it'd inadvertently cancel the browser's behavior.

Issue ProseMirror/prosemirror#933

src/index.js

@@ -129,7 +129,7 @@ export class EditorView {
         : state.scrollToSelection > prev.scrollToSelection ? "to selection" : "preserve"
     let updateDoc = redraw || !this.docView.matchesNode(state.doc, outerDeco, innerDeco)
     let updateSel = updateDoc || !state.selection.eq(prev.selection)
-    let oldScrollPos = scroll == "preserve" && updateSel && storeScrollPos(this)
+    let oldScrollPos = scroll == "preserve" && updateSel && this.dom.style.overflowAnchor == null && storeScrollPos(this)
 
     if (updateSel) {
       this.domObserver.stop()