Revise setting text -- Notebook CodeActionsOnSave (microsoft#182918)

revise example codeaction, to an actual codeaction...

Author: Yoyokrazy

src/vs/workbench/contrib/notebook/browser/notebook.contribution.ts

@@ -921,7 +921,7 @@ configurationRegistry.registerConfiguration({
 			default: false
 		},
 		[NotebookSetting.codeActionsOnSave]: {
-			markdownDescription: nls.localize('notebook.codeActionsOnSave', "Experimental. Run a series of CodeActions for a notebook on save. CodeActions must be specified, the file must not be saved after delay, and the editor must not be shutting down. Example: `notebook.format: true`"),
+			markdownDescription: nls.localize('notebook.codeActionsOnSave', "Experimental. Run a series of CodeActions for a notebook on save. CodeActions must be specified, the file must not be saved after delay, and the editor must not be shutting down. Example: `source.fixAll: true`"),
 			type: 'object',
 			additionalProperties: {
 				type: 'boolean'