docs: register the events recipe tag

The recipe uses `tags: [perms, events, auth]` and the docs build rejects a tag
that is not in `recipe-tags.js`, so the build failed. Events is a documented
module like the others next to it in that list.

The other two complex recipes tag `events` as well, so each of their branches
carries this same one-line addition; whichever lands second resolves it.

src/docs/src/recipe-tags.js

@@ -12,6 +12,7 @@ const recipeTags = {
     kv: 'Key-Value',
     hosting: 'Hosting',
     workers: 'Workers',
+    events: 'Events',
     email: 'Email',
     ui: 'UI',
     teams: 'Teams',