fix: remove spaces around em dash (Vale lint)

Author: sejori

src/oss/python/integrations/chat/doubleword.mdx

@@ -29,7 +29,7 @@ The `ChatDoubleword` class itself supports:
 | :---: | :---: | :---: | :---: | :---: |
 | ✅ | ✅ | ✅ | ✅ | ✅ |
 
-Multimodal capabilities (image, audio, video) depend on the underlying model — Doubleword passes these through to models that support them.
+Multimodal capabilities (image, audio, video) depend on the underlying model—Doubleword passes these through to models that support them.
 
 ## Setup