Merge pull request #282 from matrix-org/anoa/update_trusted_web_interfaces_doc

Update link to trusted web clients in the README and attempt to future-proof

README.md

@@ -69,7 +69,7 @@ https://matrix.to/#/#matrix:matrix.org?web-instance[element.io]=chat.mozilla.org
 
 - `client`, e.g. `client=im.fluffychat`, `client=element.io`
 - `web-instance[]`, e.g. `web-instance[element.io]=chat.mozilla.org`.
-    - For [matrix.to](https://matrix.to/), we have this list of [trusted web instances](https://github.com/matrix-org/matrix.to/blob/260d2b61cdb6b0e4318bc1bd59b4e2deef86d2a5/src/open/clients/Element.js#L20-L25) configured.
+    - For [matrix.to](https://matrix.to/), we have a list of [trusted web instances configured](src/open/clients/Element.js) (see `trustedWebInstances`).
 -  `via`, e.g. `via=mozilla.org`
 
 You can discuss matrix.to in