Make sure decorations that get merged or split get redrawn

FIX: Fix an issue where mark decorations that got merged or split
weren't properly redrawn.

See https://discuss.codemirror.net/t/codemirror6-selection-match-not-merge-when-the-selection-is-repeated-characters/8871

package.json

@@ -26,7 +26,7 @@
   "sideEffects": false,
   "license": "MIT",
   "dependencies": {
-    "@codemirror/state": "^6.4.0",
+    "@codemirror/state": "^6.5.0",
     "style-mod": "^4.1.0",
     "w3c-keyname": "^2.2.4"
   },

src/docview.ts

@@ -644,6 +644,7 @@ class DecorationComparator {
   changes: number[] = []
   compareRange(from: number, to: number) { addRange(from, to, this.changes) }
   comparePoint(from: number, to: number) { addRange(from, to, this.changes) }
+  boundChange(pos: number) { addRange(pos, pos, this.changes) }
 }
 
 function findChangedDeco(a: readonly DecorationSet[], b: readonly DecorationSet[], diff: ChangeSet) {