Remove Supermaven-related code from Zed (#50537)

Follow-up of https://github.com/zed-industries/zed/pull/49317

See also https://supermaven.com/blog/sunsetting-supermaven

- N/A

docs/src/ai/overview.md

@@ -28,7 +28,7 @@ The [Inline Assistant](./inline-assistant.md) works differently: select code or
 
 [Edit Prediction](./edit-prediction.md) provides AI code completions on every keystroke. Each keypress sends a request to the prediction provider, which returns single or multi-line suggestions you accept with `tab`.
 
-The default provider is Zeta, Zed's open-source model trained on open data. You can also use GitHub Copilot, Supermaven, or Codestral.
+The default provider is Zeta, Zed's open-source model trained on open data. You can also use GitHub Copilot, or Codestral.
 
 ## Text threads
 

docs/src/completions.md

@@ -8,7 +8,7 @@ description: Zed's code completions from language servers and edit predictions.
 Zed supports two sources for completions:
 
 1. "Code Completions" provided by Language Servers (LSPs) automatically installed by Zed or via [Zed Language Extensions](languages.md).
-2. "Edit Predictions" provided by Zed's own Zeta model or by external providers like [GitHub Copilot](#github-copilot) or [Supermaven](#supermaven).
+2. "Edit Predictions" provided by Zed's own Zeta model or by external providers like [GitHub Copilot](#github-copilot).
 
 ## Language Server Code Completions {#code-completions}
 

docs/src/reference/all-settings.md

@@ -1800,17 +1800,7 @@ While other options may be changed at a runtime and should be placed under `sett
 }
 ```
 
-3. Use Supermaven as the edit prediction provider:
-
-```json [settings]
-{
-  "edit_predictions": {
-    "provider": "supermaven"
-  }
-}
-```
-
-4. Turn off edit predictions across all providers
+3. Turn off edit predictions across all providers
 
 ```json [settings]
 {