docs: Added IBM to ChatModelTabs and EmbeddingTabs (#29774)

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Added IBM to ChatModelTabs and EmbeddingTabs

- [x] **Lint and test**: Run `make format`, `make lint` and `make test`
from the root of the package(s) you've modified. See contribution
guidelines for more: https://python.langchain.com/docs/contributing/

docs/src/theme/ChatModelTabs.js

@@ -191,6 +191,19 @@ ${llmVarName} = AzureChatOpenAI(
       apiKeyName: "TOGETHER_API_KEY",
       packageName: "langchain[together]",
     },
+    {
+      value: "ibm",
+      label: "IBM",
+      text: `from langchain_ibm import ChatWatsonx
+
+${llmVarName} = ChatWatsonx(
+    model_id="ibm/granite-34b-code-instruct", 
+    url="https://us-south.ml.cloud.ibm.com", 
+    project_id="<WATSONX PROJECT_ID>"
+)`,
+      apiKeyName: "WATSONX_APIKEY",
+      packageName: "langchain-ibm",
+    },
     {
       value: "databricks",
       label: "Databricks",

docs/src/theme/EmbeddingTabs.js

@@ -27,6 +27,8 @@ export default function EmbeddingTabs(props) {
       hideNvidia,
       voyageaiParams,
       hideVoyageai,
+      ibmParams,
+      hideIBM,
       fakeEmbeddingParams,
       hideFakeEmbedding,
       customVarName,
@@ -45,6 +47,8 @@ export default function EmbeddingTabs(props) {
     const nomicsParamsOrDefault = nomicParams ?? `model="nomic-embed-text-v1.5"`;
     const nvidiaParamsOrDefault = nvidiaParams ?? `model="NV-Embed-QA"`;
     const voyageaiParamsOrDefault = voyageaiParams ?? `model="voyage-3"`;
+    const ibmParamsOrDefault = ibmParams ?? 
+      `\n    model_id="ibm/slate-125m-english-rtrvr,\n    url="https://us-south.ml.cloud.ibm.com",\n    project_id="<WATSONX PROJECT_ID>",\n`;
     const fakeEmbeddingParamsOrDefault = fakeEmbeddingParams ?? `size=4096`;
 
     const embeddingVarName = customVarName ?? "embeddings";
@@ -149,6 +153,15 @@ export default function EmbeddingTabs(props) {
         default: false,
         shouldHide: hideVoyageai,
       },
+      {
+        value: "IBM",
+        label: "IBM",
+        text: `from langchain_ibm import WatsonxEmbeddings\n\n${embeddingVarName} = WatsonxEmbeddings(${ibmParamsOrDefault})`,
+        apiKeyName: "WATSONX_APIKEY",
+        packageName: "langchain-ibm",
+        default: false,
+        shouldHide: hideIBM,
+      },
       {
         value: "Fake",
         label: "Fake",