Docs: more about ANN

[azevaykin]

Changelog entry

Add some phrases about ANN vector search.

Changelog category

• Documentation (changelog entry is not required)

Description for reviewers

...

[github-actions]

⚪ 2025-06-20 07:08:28 UTC Pre-commit check linux-x86_64-relwithdebinfo for 9b7cc02 has started.
⚪ 2025-06-20 07:09:14 UTC Artifacts will be uploaded here
⚪ 2025-06-20 07:12:11 UTC ya make is running...
🟢 2025-06-20 07:12:16 UTC Tests successful.

Test history | Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
0	0	0	0	0	0

🟢 2025-06-20 07:12:22 UTC Build successful.

[github-actions]

🟢 2025-06-20 07:08:56 UTC The validation of the Pull Request description is successful.

[github-actions]

⚪ 2025-06-20 07:10:36 UTC Pre-commit check linux-x86_64-release-asan for 9b7cc02 has started.
⚪ 2025-06-20 07:10:40 UTC Artifacts will be uploaded here
⚪ 2025-06-20 07:13:07 UTC ya make is running...
🟢 2025-06-20 07:13:13 UTC Tests successful.

Test history | Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
0	0	0	0	0	0

🟢 2025-06-20 07:13:18 UTC Build successful.

[github-actions]

✅ Documentation build

Revision built successfully
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Build logs

Warnings (2)

⚠️ en/concepts/glossary.md: 165: MD009 / no-trailing-spaces Trailing spaces [Expected: 0 or 2; Actual: 1]

⚠️ ru/concepts/glossary.md: 157: MD009 / no-trailing-spaces Trailing spaces [Expected: 0 or 2; Actual: 1]