docs: Improve MCP-related pages (#32422)

While creating a new MCP extension this weekend, I visited these pages
and it felt like they could be improved a little bit. I'm renaming the
MCP-related page under the /extension directory to use the "MCP"
acronym, instead of "context servers".

Release Notes:

- N/A

docs/src/extensions/context-servers.md

@@ -1,39 +0,0 @@
-# Context Servers
-
-Extensions may provide [context servers](../ai/mcp.md) for use in the Assistant.
-
-## Example extension
-
-To see a working example of an extension that provides context servers, check out the [`postgres-context-server` extension](https://github.com/zed-extensions/postgres-context-server).
-
-This extension can be [installed as a dev extension](./developing-extensions.md#developing-an-extension-locally) if you want to try it out for yourself.
-
-## Defining context servers
-
-A given extension may provide one or more context servers. Each context server must be registered in the `extension.toml`:
-
-```toml
-[context_servers.my-context-server]
-```
-
-Then, in the Rust code for your extension, implement the `context_server_command` method on your extension:
-
-```rust
-impl zed::Extension for MyExtension {
-    fn context_server_command(
-        &mut self,
-        context_server_id: &ContextServerId,
-        project: &zed::Project,
-    ) -> Result<zed::Command> {
-        Ok(zed::Command {
-            command: get_path_to_context_server_executable()?,
-            args: get_args_for_context_server()?,
-            env: get_env_for_context_server()?,
-        })
-    }
-}
-```
-
-This method should return the command to start up a context server, along with any arguments or environment variables necessary for it to function.
-
-If you need to download the context server from an external source—like GitHub Releases or npm—you can also do this here.

docs/src/extensions/developing-extensions.md

@@ -8,7 +8,7 @@ Extensions can add the following capabilities to Zed:
 - [Themes](./themes.md)
 - [Icon Themes](./icon-themes.md)
 - [Slash Commands](./slash-commands.md)
-- [Context Servers](./context-servers.md)
+- [MCP Servers](./mcp-extensions.md)
 
 ## Developing an Extension Locally
 

docs/src/extensions/mcp-extensions.md

@@ -0,0 +1,44 @@
+# MCP Server Extensions
+
+[Model Context Protocol servers](../ai/mcp.md) can be exposed as extensions for use in the Agent Panel.
+
+## Defining MCP Extensions
+
+A given extension may provide one or more MCP servers.
+Each MCP server must be registered in the `extension.toml`:
+
+```toml
+[context_servers.my-context-server]
+```
+
+Then, in the Rust code for your extension, implement the `context_server_command` method on your extension:
+
+```rust
+impl zed::Extension for MyExtension {
+    fn context_server_command(
+        &mut self,
+        context_server_id: &ContextServerId,
+        project: &zed::Project,
+    ) -> Result<zed::Command> {
+        Ok(zed::Command {
+            command: get_path_to_context_server_executable()?,
+            args: get_args_for_context_server()?,
+            env: get_env_for_context_server()?,
+        })
+    }
+}
+```
+
+This method should return the command to start up an MCP server, along with any arguments or environment variables necessary for it to function.
+
+If you need to download the MCP server from an external source—like GitHub Releases or npm—you can also do that in this function.
+
+## Available Extensions
+
+Check out all the MCP servers that have already been exposed as Zed extensions [on Zed's site](https://zed.dev/extensions?filter=context-servers).
+
+We recommend taking a look at their repositories as a way to understand how they are generally created and structured.
+
+## Testing
+
+To test your new MCP server extension, you can [install it as a dev extension](./developing-extensions.md#developing-an-extension-locally).