Add custom vector fields and text fields for OpenSearch (#2652)

**Description**
Add custom vector field name and text field name while indexing and
querying for OpenSearch

**Issues**
langchain-ai/langchain#2500

Signed-off-by: Naveen Tatikonda <navtat@amazon.com>

modules/indexes/vectorstores/examples/opensearch.ipynb

@@ -55,7 +55,7 @@
    },
    "outputs": [],
    "source": [
-    "docsearch = OpenSearchVectorSearch.from_texts(texts, embeddings, opensearch_url=\"http://localhost:9200\")\n",
+    "docsearch = OpenSearchVectorSearch.from_documents(docs, embeddings, opensearch_url=\"http://localhost:9200\")\n",
     "\n",
     "query = \"What did the president say about Ketanji Brown Jackson\"\n",
     "docs = docsearch.similarity_search(query)"
@@ -94,7 +94,7 @@
    },
    "outputs": [],
    "source": [
-    "docsearch = OpenSearchVectorSearch.from_texts(texts, embeddings, opensearch_url=\"http://localhost:9200\", engine=\"faiss\", space_type=\"innerproduct\", ef_construction=256, m=48)\n",
+    "docsearch = OpenSearchVectorSearch.from_documents(docs, embeddings, opensearch_url=\"http://localhost:9200\", engine=\"faiss\", space_type=\"innerproduct\", ef_construction=256, m=48)\n",
     "\n",
     "query = \"What did the president say about Ketanji Brown Jackson\"\n",
     "docs = docsearch.similarity_search(query)"
@@ -133,7 +133,7 @@
    },
    "outputs": [],
    "source": [
-    "docsearch = OpenSearchVectorSearch.from_texts(texts, embeddings, opensearch_url=\"http://localhost:9200\", is_appx_search=False)\n",
+    "docsearch = OpenSearchVectorSearch.from_documents(docs, embeddings, opensearch_url=\"http://localhost:9200\", is_appx_search=False)\n",
     "\n",
     "query = \"What did the president say about Ketanji Brown Jackson\"\n",
     "docs = docsearch.similarity_search(\"What did the president say about Ketanji Brown Jackson\", k=1, search_type=\"script_scoring\")"
@@ -172,10 +172,10 @@
    },
    "outputs": [],
    "source": [
-    "docsearch = OpenSearchVectorSearch.from_texts(texts, embeddings, opensearch_url=\"http://localhost:9200\", is_appx_search=False)\n",
+    "docsearch = OpenSearchVectorSearch.from_documents(docs, embeddings, opensearch_url=\"http://localhost:9200\", is_appx_search=False)\n",
     "filter = {\"bool\": {\"filter\": {\"term\": {\"text\": \"smuggling\"}}}}\n",
     "query = \"What did the president say about Ketanji Brown Jackson\"\n",
-    "docs = docsearch.similarity_search(\"What did the president say about Ketanji Brown Jackson\", search_type=\"painless_scripting\", space_type=\"cosinesimil\", pre_filter=filter)"
+    "docs = docsearch.similarity_search(\"What did the president say about Ketanji Brown Jackson\", search_type=\"painless_scripting\", space_type=\"cosineSimilarity\", pre_filter=filter)"
    ]
   },
   {
@@ -238,4 +238,4 @@
  },
  "nbformat": 4,
  "nbformat_minor": 5
-}
+}