Closes#13464
Adds a note to the Indexes docs for localized fields:
- Indexing a `localized: true` field creates one index per locale path
(e.g. `slug.en`, `slug.da-dk`), which can grow index count on MongoDB.
- Recommends defining explicit indexes via collection-level `indexes`
for only the locale paths you actually query.
- Includes a concrete example (index `slug.en` only).
Docs-only change.
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Co-authored-by: German Jablonski <43938777+GermanJablo@users.noreply.github.com>
379ef87d84