Support /subtlenotify

In oldclient, it'll be treated like `/nonotify`. In newclient, it'll
do a subtle notification, which according to #2641 is desirable
in some cases.

play.pokemonshowdown.com/js/client-mainmenu.js

@@ -1254,6 +1254,7 @@
 			case 'raw':
 				return { message: '<div class="chat chatmessage-' + toID(name) + '">' + BattleLog.sanitizeHTML(target) + '</div>', noNotify: isNotPM };
 			case 'nonotify':
+			case 'subtlenotify':
 				return { message: '<div class="chat">' + timestamp + BattleLog.sanitizeHTML(target) + '</div>', noNotify: true };
 			case 'challenge':
 				return { challenge: target };

play.pokemonshowdown.com/src/battle-log.ts

@@ -142,7 +142,7 @@ export class BattleLog {
 		}
 		let divClass = 'chat';
 		let divHTML = '';
-		let noNotify: boolean | undefined;
+		let noNotify: boolean | 'subtle' | undefined;
 		if (!['name', 'n'].includes(args[0])) this.lastRename = null;
 		switch (args[0]) {
 		case 'chat': case 'c': case 'c:':
@@ -1232,7 +1232,7 @@ export class BattleLog {
 
 	parseChatMessage(
 		message: string, name: string, timestamp: string, isHighlighted?: boolean
-	): [divClass: string, divHTML: string, noNotify?: boolean] {
+	): [divClass: string, divHTML: string, noNotify?: boolean | 'subtle'] {
 		let showMe = !BattleLog.prefs('chatformatting')?.hideme;
 		let group = ' ';
 		if (!/[A-Za-z0-9]/.test(name.charAt(0))) {
@@ -1320,6 +1320,8 @@ export class BattleLog {
 			return ['chat', BattleLog.sanitizeHTML(target), true];
 		case 'nonotify':
 			return ['chat', BattleLog.sanitizeHTML(target), true];
+		case 'subtlenotify':
+			return ['chat', BattleLog.sanitizeHTML(target), 'subtle'];
 		default:
 			// Not a command or unsupported. Parsed as a normal chat message.
 			if (!name) {

play.pokemonshowdown.com/src/panel-chat.tsx

@@ -158,6 +158,8 @@ export class ChatRoom extends PSRoom {
 						title: `${this.title}`,
 						body: textContent,
 					});
+				} else if (noNotify === 'subtle') {
+					this.subtleNotify();
 				}
 			} else {
 				this.subtleNotify();