Fix duplication in API docs

Author: amrit110

docs/api.md

@@ -2,23 +2,15 @@
 
 This section documents the Python API for vector-inference.
 
-## Client
-
-::: vec_inf.client
-    options:
-      show_root_heading: true
-      show_root_full_path: true
-      show_submodules: true
-
-## Client API
+## Client Interface
 
 ::: vec_inf.client.api.VecInfClient
     options:
       show_root_heading: true
       show_root_full_path: true
       members: true
 
-## Models
+## Data Models
 
 ::: vec_inf.client._models
     options: