Mentions as links rte (#10422)

* bumps the RTE dependency to introduce user/room mention handling
* adds autocomplete behaviour to allow users to insert user and room mentions as links
* sets up tests for the autocomplete behaviour

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": "^1.4.0",
         "@matrix-org/react-sdk-module-api": "^0.0.4",
         "@sentry/browser": "^7.0.0",
         "@sentry/tracing": "^7.0.0",