docs(rerankers): align reranker config docs with v3 SDK source

docs/components/rerankers/models/sentence_transformer.mdx

@@ -39,7 +39,7 @@ config = {
             "model": "gpt-4o-mini"
         }
     },
-    "rerank": {
+    "reranker": {
         "provider": "sentence_transformer",
         "config": {
             "model": "cross-encoder/ms-marco-MiniLM-L-6-v2",
@@ -60,7 +60,7 @@ For better performance, use GPU acceleration:
 
 ```python Python
 config = {
-    "rerank": {
+    "reranker": {
         "provider": "sentence_transformer",
         "config": {
             "model": "cross-encoder/ms-marco-MiniLM-L-6-v2",
@@ -80,7 +80,7 @@ from mem0 import Memory
 config = {
     "vector_store": {"provider": "chroma"},
     "llm": {"provider": "openai", "config": {"model": "gpt-4o-mini"}},
-    "rerank": {
+    "reranker": {
         "provider": "sentence_transformer",
         "config": {
             "model": "cross-encoder/ms-marco-MiniLM-L-6-v2",
@@ -117,7 +117,7 @@ You can use any HuggingFace cross-encoder model:
 ```python Python
 # Using a different model
 config = {
-    "rerank": {
+    "reranker": {
         "provider": "sentence_transformer", 
         "config": {
             "model": "cross-encoder/stsb-distilroberta-base",