### What?
Updates the join field documentation.
Mentions:
* Now you can specify an array of `collection` -
https://github.com/payloadcms/payload/pull/10919
* Querying limitation for join fields, planned
https://github.com/payloadcms/payload/discussions/9683
* Querying limitation for joined documents when the join field has an
array of `collection` for fields inside arrays and blocks.
### Why?
To have up to date documentation for an array of `collection` and so
users can know about limitations.
### How?
Updates the file on path `docs/fields/join.mdx`.
0d7cf3fca2