Docs: explain how to use Vector Search maxResultCount combined with additional criteria

Is there an existing issue?

• I have searched existing issues

Build info

• objectbox version: [4.0.1]
• Flutter/Dart version: [Flutter 3.22.3, Dart 3.4.4]
• Build OS: [Windows 11]
• Deployment OS or device: [Android 10, API29, Huawei P30 Pro]

Steps to reproduce

TODO Tell us exactly how to reproduce the problem.

1. create a query for vector search, I did with embeddings, want to have 2 results:
   final query = box
   .query(Message_.embedding.nearestNeighborsF32(search_embedding, 2))
   .build();
   => Works fine

2. combine the search with a second criteria.
   final query = box
   .query(
   Message_.embedding.nearestNeighborsF32(search_embedding, 2)
   .and( Message_.chatid.equals(character))
   ).build();

=> Results given are 0 or 1 or 2 results. Expected are 2 results.

I assume that the first condition is fulfilled, it searches for 2 results independent of the second criteria. Then second criteria is applied and from 2 results only 1 or 0 or 2 remain.

Expected behavior

Find 2 results with vector search also with additional conditions.

Actual behavior

Amount of results vary, depending on if the found results of step 1 fulfill the second criteria or not.

Note after analysis

In your documentation the following I assume will also not work as expected:
https://docs.objectbox.io/on-device-vector-search
final query = box
.query(City_.location.nearestNeighborsF32(madrid, 2)
.and(City_.name.startsWith("B")))
.build();

Just figured out that I could probably use "limit" from here https://docs.objectbox.io/queries in the "query" and leave the limit out in the "vector search" (leave it out is not possible, I just set it to several million). Would just be a question to you how this will work regarding ressources, how the vector search is implemented, but assume that will work.
Another workaround for me might be to work with a stream and interrupt the stream after 2 results.

So it might not be a bug, maybe just the documentation above needs to be adopted.

Start with the on-device vector search and queries documentation linked in the issue, comparing the nearest-neighbor count with an additional criterion and query limit. Update the documentation to explain the result-count behavior and the supported way to obtain the requested number of matching results. Done when the examples and resource implications are clear.