Enable awaitWriteFinish for the db config file watcher (#1872)

extensions/ql-vscode/src/databases/config/db-config-store.ts

@@ -166,7 +166,18 @@ export class DbConfigStore extends DisposableObject {
   }
 
   private watchConfig(): void {
-    this.configWatcher = chokidar.watch(this.configPath).on("change", () => {
+    this.configWatcher = chokidar
+      .watch(this.configPath, {
+        // In some cases, change events are emitted while the file is still
+        // being written. The awaitWriteFinish option tells the watcher to
+        // poll the file size, holding its add and change events until the size
+        // does not change for a configurable amount of time. We set that time
+        // to 1 second, but it may need to be adjusted if there are issues.
+        awaitWriteFinish: {
+          stabilityThreshold: 1000,
+        },
+      })
+      .on("change", () => {
         this.readConfigSync();
       });
   }