Mark all properties in ExtensionContext readonly

These values should not be modified

src/vs/vscode.d.ts

@@ -4754,24 +4754,24 @@ declare module 'vscode' {
 		 * An array to which disposables can be added. When this
 		 * extension is deactivated the disposables will be disposed.
 		 */
-		subscriptions: { dispose(): any }[];
+		readonly subscriptions: { dispose(): any }[];
 
 		/**
 		 * A memento object that stores state in the context
 		 * of the currently opened [workspace](#workspace.workspaceFolders).
 		 */
-		workspaceState: Memento;
+		readonly workspaceState: Memento;
 
 		/**
 		 * A memento object that stores state independent
 		 * of the current opened [workspace](#workspace.workspaceFolders).
 		 */
-		globalState: Memento;
+		readonly globalState: Memento;
 
 		/**
 		 * The absolute file path of the directory containing the extension.
 		 */
-		extensionPath: string;
+		readonly extensionPath: string;
 
 		/**
 		 * Get the absolute path of a resource contained in the extension.
@@ -4789,7 +4789,7 @@ declare module 'vscode' {
 		 * Use [`workspaceState`](#ExtensionContext.workspaceState) or
 		 * [`globalState`](#ExtensionContext.globalState) to store key value data.
 		 */
-		storagePath: string | undefined;
+		readonly storagePath: string | undefined;
 
 		/**
 		 * An absolute file path in which the extension can store global state.
@@ -4798,14 +4798,14 @@ declare module 'vscode' {
 		 *
 		 * Use [`globalState`](#ExtensionContext.globalState) to store key value data.
 		 */
-		globalStoragePath: string;
+		readonly globalStoragePath: string;
 
 		/**
 		 * An absolute file path of a directory in which the extension can create log files.
 		 * The directory might not exist on disk and creation is up to the extension. However,
 		 * the parent directory is guaranteed to be existent.
 		 */
-		logPath: string;
+		readonly logPath: string;
 	}
 
 	/**