fix: kb files path (#189)

Author: bryantanderson

fern/community/knowledgebase.mdx

@@ -28,7 +28,7 @@ Navigate to Platform > Files and upload your custom files in Markdown, PDF, plai
 
 <Frame caption="Adding files to your Knowledge Base">
   <img
-    src="./static/images/knowledge-base/files.png"
+    src="../static/images/knowledge-base/files.png"
     alt="Adding files to your Knowledge Base"
   />
 </Frame>