terminal: make typeahead style more friendly

Fixes https://github.com/microsoft/vscode/issues/109590

src/vs/workbench/contrib/terminal/browser/terminalTypeAheadAddon.ts

@@ -9,7 +9,7 @@ import { Emitter } from 'vs/base/common/event';
 import { Disposable } from 'vs/base/common/lifecycle';
 import { ITelemetryService } from 'vs/platform/telemetry/common/telemetry';
 import { TerminalConfigHelper } from 'vs/workbench/contrib/terminal/browser/terminalConfigHelper';
-import { IBeforeProcessDataEvent, ITerminalProcessManager } from 'vs/workbench/contrib/terminal/common/terminal';
+import { IBeforeProcessDataEvent, ITerminalConfiguration, ITerminalProcessManager } from 'vs/workbench/contrib/terminal/common/terminal';
 import type { IBuffer, IBufferCell, ITerminalAddon, Terminal } from 'xterm';
 
 const ESC = '\x1b';
@@ -849,13 +849,22 @@ const getBufferCellAttributes = (cell: IBufferCell) => cell.isAttributeDefault()
 		cell.isBgDefault() && `${CSI}49m`,
 	].filter(seq => !!seq).join('');
 
-const parseTypeheadStyle = (style: string | number) => {
-	if (typeof style === 'number') {
-		return `${CSI}${style}m`;
+const parseTypeheadStyle = (style: ITerminalConfiguration['typeaheadStyle']) => {
+	switch (style) {
+		case 'bold':
+			return `${CSI}1m`;
+		case 'dim':
+			return `${CSI}2m`;
+		case 'italic':
+			return `${CSI}3m`;
+		case 'underlined':
+			return `${CSI}4m`;
+		case 'inverted':
+			return `${CSI}7m`;
+		default:
+			const { r, g, b } = Color.fromHex(style).rgba;
+			return `${CSI}38;2;${r};${g};${b}m`;
 	}
-
-	const { r, g, b } = Color.fromHex(style).rgba;
-	return `${CSI}38;2;${r};${g};${b}m`;
 };
 
 export class TypeAheadAddon extends Disposable implements ITerminalAddon {

src/vs/workbench/contrib/terminal/common/terminal.ts

@@ -136,7 +136,7 @@ export interface ITerminalConfiguration {
 	unicodeVersion: '6' | '11';
 	experimentalLinkProvider: boolean;
 	typeaheadThreshold: number;
-	typeaheadStyle: number | string;
+	typeaheadStyle: 'bold' | 'dim' | 'italic' | 'underlined' | 'inverted' | string;
 	serverSpawn: boolean;
 	enablePersistentSessions: boolean;
 }

src/vs/workbench/contrib/terminal/common/terminalConfiguration.ts

@@ -360,20 +360,12 @@ export const terminalConfiguration: IConfigurationNode = {
 		},
 		'terminal.integrated.typeaheadStyle': {
 			description: localize('terminal.integrated.typeaheadStyle', "Experimental: terminal style of typeahead text, either a font style or an RGB color."),
-			default: 2,
+			default: 'dim',
 			oneOf: [
 				{
-					type: 'integer',
-					default: 2,
-					enum: [0, 1, 2, 3, 4, 7],
-					enumDescriptions: [
-						localize('terminal.integrated.typeaheadStyle.0', 'Normal'),
-						localize('terminal.integrated.typeaheadStyle.1', 'Bold'),
-						localize('terminal.integrated.typeaheadStyle.2', 'Dim'),
-						localize('terminal.integrated.typeaheadStyle.3', 'Italic'),
-						localize('terminal.integrated.typeaheadStyle.4', 'Underlined'),
-						localize('terminal.integrated.typeaheadStyle.7', 'Inverted'),
-					]
+					type: 'string',
+					default: 'dim',
+					enum: ['bold', 'dim', 'italic', 'underlined', 'inverted'],
 				},
 				{
 					type: 'string',