Add mentions as links to rte (#10463)

* adds autocomplete behaviour for mentions in rich text editor
* allows adding mentions as links
* adds tests

package.json

@@ -61,7 +61,7 @@
     "dependencies": {
         "@babel/runtime": "^7.12.5",
         "@matrix-org/analytics-events": "^0.5.0",
-        "@matrix-org/matrix-wysiwyg": "^1.1.1",
+        "@matrix-org/matrix-wysiwyg": "^1.4.1",
         "@matrix-org/react-sdk-module-api": "^0.0.4",
         "@sentry/browser": "^7.0.0",
         "@sentry/tracing": "^7.0.0",