feat: adds hybrid search for sync VS interface [4/N]

[vishwarajanand]

Adds doc blocks for Sync VS towards hybrid search config.

Test Log

(venv311) (base) ➜  langchain-postgres git:(hybrid_search_4) ✗ python -m pytest -vvv tests/unit_tests/v2/test_pg_vectorstore_search.py -k _hybrid_search
/usr/local/google/home/vishwarajanand/github/langchain-postgres/venv311/lib/python3.11/site-packages/pytest_asyncio/plugin.py:217: PytestDeprecationWarning: The configuration option "asyncio_default_fixture_loop_scope" is unset.
The event loop scope for asynchronous fixtures will default to the fixture caching scope. Future versions of pytest-asyncio will default the loop scope for asynchronous fixtures to function scope. Set the default fixture loop scope explicitly in order to avoid unexpected behavior in the future. Valid fixture loop scopes are: "function", "class", "module", "package", "session"

  warnings.warn(PytestDeprecationWarning(_DEFAULT_FIXTURE_LOOP_SCOPE_UNSET))
======================================================================== test session starts ========================================================================
platform linux -- Python 3.11.12, pytest-8.3.5, pluggy-1.6.0 -- /usr/local/google/home/vishwarajanand/github/langchain-postgres/venv311/bin/python
cachedir: .pytest_cache
rootdir: /usr/local/google/home/vishwarajanand/github/langchain-postgres
configfile: pyproject.toml
plugins: anyio-4.9.0, timeout-2.4.0, asyncio-0.26.0, langsmith-0.3.42
timeout: 30.0s
timeout method: signal
timeout func_only: False
asyncio: mode=Mode.AUTO, asyncio_default_fixture_loop_scope=None, asyncio_default_test_loop_scope=function
collected 108 items / 106 deselected / 2 selected                                                                                                                   

tests/unit_tests/v2/test_pg_vectorstore_search.py::TestVectorStoreSearch::test_asimilarity_hybrid_search PASSED                                               [ 50%]
tests/unit_tests/v2/test_pg_vectorstore_search.py::TestVectorStoreSearchSync::test_similarity_hybrid_search PASSED                                            [100%]

========================================================================= warnings summary ==========================================================================
venv311/lib/python3.11/site-packages/pytest_asyncio/plugin.py:1140: 10 warnings
tests/unit_tests/v2/test_pg_vectorstore_search.py: 1 warning
  /usr/local/google/home/vishwarajanand/github/langchain-postgres/venv311/lib/python3.11/site-packages/pytest_asyncio/plugin.py:1140: PytestDeprecationWarning: The "scope" keyword argument to the asyncio marker has been deprecated. Please use the "loop_scope" argument instead.
  
    warnings.warn(PytestDeprecationWarning(_MARKER_SCOPE_KWARG_DEPRECATION_WARNING))

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
======================================================================== slowest 5 durations ========================================================================
8.28s setup    tests/unit_tests/v2/test_pg_vectorstore_search.py::TestVectorStoreSearch::test_asimilarity_hybrid_search
8.12s setup    tests/unit_tests/v2/test_pg_vectorstore_search.py::TestVectorStoreSearchSync::test_similarity_hybrid_search
4.72s call     tests/unit_tests/v2/test_pg_vectorstore_search.py::TestVectorStoreSearchSync::test_similarity_hybrid_search
4.16s call     tests/unit_tests/v2/test_pg_vectorstore_search.py::TestVectorStoreSearch::test_asimilarity_hybrid_search
1.31s teardown tests/unit_tests/v2/test_pg_vectorstore_search.py::TestVectorStoreSearch::test_asimilarity_hybrid_search
========================================================== 2 passed, 106 deselected, 11 warnings in 28.74s ==========================================================
(venv311) (base) ➜  langchain-postgres git:(hybrid_search_4) ✗

[dishaprakash]

LGTM