Support llmGenerated property on CodeAction (#2020)

* add new property to codeAction

* address feedback to use CodeActioTag

* wording tweaks

* add client capability

Author: StellaHuang95

_specifications/lsp/3.18/language/codeAction.md

@@ -107,6 +107,19 @@ export interface CodeActionClientCapabilities {
 	 * @proposed
 	 */
 	 documentationSupport?: boolean;
+
+	/**
+	 * Client supports the tag property on a code action. Clients
+	 * supporting tags have to handle unknown tags gracefully.
+	 *
+	 * @since 3.18.0 - proposed
+	 */
+	tagSupport?: {
+		/**
+		 * The tags supported by the client.
+		 */
+		valueSet: CodeActionTag[];
+	}; 
 }
 ```
 
@@ -412,6 +425,23 @@ export namespace CodeActionTriggerKind {
 export type CodeActionTriggerKind = 1 | 2;
 ```
 
+<div class="anchorHolder"><a href="#codeActionTag" name="codeActionTag" class="linkableAnchor"></a></div>
+
+```typescript
+/**
+ * Code action tags are extra annotations that tweak the behavior of a code action.
+ *
+ * @since 3.18.0 - proposed
+ */
+export namespace CodeActionTag {
+	/**
+	 * Marks the code action as LLM-generated.
+	 */
+	export const LLMGenerated = 1;
+}
+export type CodeActionTag = 1;
+```
+
 _Response_:
 * result: `(Command | CodeAction)[]` \| `null` where `CodeAction` is defined as follows:
 
@@ -505,6 +535,13 @@ export interface CodeAction {
 	 * @since 3.16.0
 	 */
 	data?: LSPAny;
+
+	/**
+ 	 * Tags for this code action.
+	 *
+	 * @since 3.18.0 - proposed
+	 */
+	tags?: CodeActionTag[];
 }
 ```
 * partial result: `(Command | CodeAction)[]`

_specifications/lsp/3.18/metaModel/metaModel.json

@@ -5709,6 +5709,19 @@
 					"optional": true,
 					"documentation": "A data entry field that is preserved on a code action between\na `textDocument/codeAction` and a `codeAction/resolve` request.\n\n@since 3.16.0",
 					"since": "3.16.0"
+				},
+				{
+					"name": "tags",
+					"type": {
+						"kind": "array",
+						"element": {
+							"kind": "reference",
+							"name": "CodeActionTag"
+						}
+					},
+					"optional": true,
+					"documentation": "Tags for this code action.\n\n@since 3.18.0 - proposed",
+					"since": "3.18.0 - proposed"
 				}
 			],
 			"documentation": "A code action represents a change that can be performed in code, e.g. to fix a problem or\nto refactor code.\n\nA CodeAction must set either `edit` and/or a `command`. If both are supplied, the `edit` is applied first, then the `command` is executed."
@@ -12511,10 +12524,38 @@
 					"documentation": "Whether the client supports documentation for a class of\ncode actions.\n\n@since 3.18.0\n@proposed",
 					"since": "3.18.0",
 					"proposed": true
+				},
+				{
+					"name": "tagSupport",
+					"type": {
+						"kind": "reference",
+						"name": "CodeActionTagOptions"
+					},
+					"optional": true,
+					"documentation": "Client supports the tag property on a code action. Clients\nsupporting tags have to handle unknown tags gracefully.\n\n@since 3.18.0 - proposed",
+					"since": "3.18.0 - proposed"
 				}
 			],
 			"documentation": "The Client Capabilities of a {@link CodeActionRequest}."
 		},
+		{
+			"name": "CodeActionTagOptions",
+			"properties": [
+				{
+					"name": "valueSet",
+					"type": {
+						"kind": "array",
+						"element": {
+							"kind": "reference",
+							"name": "CodeActionTag"
+						}
+					},
+					"documentation": "The tags supported by the client."
+				}
+			],
+			"documentation": "@since 3.18.0 - proposed",
+			"since": "3.18.0 - proposed"
+		},
 		{
 			"name": "CodeLensClientCapabilities",
 			"properties": [
@@ -14602,6 +14643,22 @@
 			"supportsCustomValues": true,
 			"documentation": "A set of predefined code action kinds"
 		},
+		{
+			"name": "CodeActionTag",
+			"type": {
+				"kind": "base",
+				"name": "uinteger"
+			},
+			"values": [
+				{
+					"name": "LLMGenerated",
+					"value": 1,
+					"documentation": "Marks the code action as LLM-generated."
+				}
+			],
+			"documentation": "Code action tags are extra annotations that tweak the behavior of a code action.\n\n@since 3.18.0 - proposed",
+			"since": "3.18.0 - proposed"
+		},
 		{
 			"name": "TraceValue",
 			"type": {