Merge #5144

5144: Exactly 512 bytes docid fails r=Kerollmops a=dureuill

# Pull Request

## Related issue
Fixes #5050 

## What does this PR do?
- Return a user error rather than an internal one for docids of exactly 512 bytes
- Fix up error message to indicate that exactly 512 bytes long docids are not supported.
- Fix up error message to reflect that index uids are actually limited to 400 bytes in length

## Impact

- Impacts docs: 
    - update [this paragraph](https://www.meilisearch.com/docs/learn/resources/known_limitations#length-of-primary-key-values) to say 511 bytes instead of 512 

Co-authored-by: Louis Dureuil <louis@meilisearch.com>

crates/meilisearch-types/src/error.rs

@@ -550,7 +550,7 @@ impl fmt::Display for deserr_codes::InvalidSimilarId {
             "the value of `id` is invalid. \
             A document identifier can be of type integer or string, \
             only composed of alphanumeric characters (a-z A-Z 0-9), hyphens (-) and underscores (_), \
-            and can not be more than 512 bytes."
+            and can not be more than 511 bytes."
         )
     }
 }