Use clearer name for csp webview element

#76489

src/vs/workbench/api/common/extHost.protocol.ts

@@ -60,7 +60,7 @@ export interface IEnvironment {
 	globalStorageHome: URI;
 	userHome: URI;
 	webviewResourceRoot: string;
-	webviewCspRule: string;
+	webviewCspSource: string;
 }
 
 export interface IStaticWorkspaceData {

src/vs/workbench/api/common/extHostCodeInsets.ts

@@ -69,8 +69,8 @@ export class ExtHostEditorInsets implements ExtHostEditorInsetsShape {
 				return toWebviewResource(that._initData, this._uuid, resource);
 			}
 
-			get cspRule(): string {
-				return that._initData.webviewCspRule;
+			get cspSource(): string {
+				return that._initData.webviewCspSource;
 			}
 
 			set options(value: vscode.WebviewOptions) {

src/vs/workbench/api/common/extHostWebview.ts

@@ -41,8 +41,8 @@ export class ExtHostWebview implements vscode.Webview {
 		return toWebviewResource(this._initData, this._uuid, resource);
 	}
 
-	public get cspRule(): string {
-		return this._initData.webviewCspRule;
+	public get cspSource(): string {
+		return this._initData.webviewCspSource;
 	}
 
 	public get html(): string {

src/vs/workbench/api/common/shared/webview.ts

@@ -8,7 +8,7 @@ import * as vscode from 'vscode';
 
 export interface WebviewInitData {
 	readonly webviewResourceRoot: string;
-	readonly webviewCspRule: string;
+	readonly webviewCspSource: string;
 }
 
 export function toWebviewResource(