Add test case for model property named "list" (#9259)

Adds test coverage for model properties using reserved keywords,
specifically "list" which is reserved in Python and other languages.

## Changes

- **`main.tsp`**: Added `ModelWithList` model with `list` property in
`ModelProperties` namespace, following existing pattern for reserved
word testing
- **`mockapi.ts`**: Added `SpecialWords_ModelProperties_withList`
scenario expecting `{"list": "ok"}` payload
- **Special words list**: Updated documentation to include "list" in the
enumerated reserved words

## Example

```typespec
model ModelWithList {
  list: string;
}

@Scenario
@route("list")
op withList(@Body body: ModelWithList): void;
```

Validates that generators properly escape or handle the `list` property
name when generating client code.

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<details>

<summary>Original prompt</summary>

> 
> ----
> 
> *This section details on the original issue you should resolve*
> 
> <issue_title>[specs] new test case for model whose property is named
"list"</issue_title>
> <issue_description>To cover scenario
#9248, we need a new test
case in
https://github.com/microsoft/typespec/blob/main/packages/http-specs/specs/special-words/main.tsp
that it has model property named "list"
> 
> NOTE:
> - DO add changelog in
https://github.com/microsoft/typespec/tree/main/.chronus/changes
> - DO run command
https://github.com/microsoft/typespec/blob/664978b3cf7399e43e2823d3a69043203e740109/packages/http-specs/package.json#L14
under
https://github.com/microsoft/typespec/blob/main/packages/http-specs to
check all ci items.</issue_description>
> 
> ## Comments on the Issue (you are @copilot in this section)
> 
> <comments>
> </comments>
> 


</details>



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- Fixes #9258

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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: msyyc <70930885+msyyc@users.noreply.github.com>
Co-authored-by: Yuchao Yan <yuchaoyan@microsoft.com>

Author: Copilot

.chronus/changes/add-list-property-test-2025-12-22-08-19-30.md

@@ -0,0 +1,7 @@
+---
+changeKind: internal
+packages:
+  - "@typespec/http-specs"
+---
+
+Add test case for model property named "list" to cover special word scenarios

packages/http-specs/spec-summary.md

@@ -3621,6 +3621,18 @@ Send
 { "SameAsModel": "ok" }
 ```
 
+### SpecialWords_ModelProperties_withList
+
+- Endpoint: `get /special-words/model-properties/list`
+
+Verify that a property can be named "list", which is a reserved word in many languages like Python.
+
+Send
+
+```json
+{ "list": "ok" }
+```
+
 ### SpecialWords_Models_and
 
 - Endpoint: `get /special-words/models/and`

packages/http-specs/specs/special-words/main.tsp

@@ -34,6 +34,7 @@ using Spector;
  * in
  * is
  * lambda
+ * list
  * not
  * or
  * pass
@@ -269,4 +270,22 @@ namespace ModelProperties {
     """)
   @route("dict-methods")
   op dictMethods(@body body: DictMethods): void;
+
+  // Test for model property named "list" which is a reserved word in many languages
+  model ModelWithList {
+    list: string;
+  }
+
+  @scenario
+  @scenarioDoc("""
+    Verify that a property can be named "list", which is a reserved word in many languages like Python.
+    
+    Send
+    
+    ```json
+    {"list": "ok"}
+    ```
+    """)
+  @route("list")
+  op withList(@body body: ModelWithList): void;
 }

packages/http-specs/specs/special-words/mockapi.ts

@@ -39,6 +39,20 @@ Scenarios.SpecialWords_ModelProperties_dictMethods = passOnSuccess({
   kind: "MockApiDefinition",
 });
 
+Scenarios.SpecialWords_ModelProperties_withList = passOnSuccess({
+  uri: "/special-words/model-properties/list",
+  method: "post",
+  request: {
+    body: json({
+      list: "ok",
+    }),
+  },
+  response: {
+    status: 204,
+  },
+  kind: "MockApiDefinition",
+});
+
 function createModelsTests(uri: string) {
   return passOnSuccess({
     uri,