Add "occupied help channel" embed

https://discord.com/channels/508357248330760243/508357683506708514/821851432235433984

^As @gencha#69 points out, once a channel has been claimed, there's
still a big 'ol embed just a little ways up that describes the channel
as available -- which might contribute to help-channel sniping.

This adds a new embed which marks the channel as occupied. It does not
use it anywhere yet; that'll come soon.

Author: smichel17

src/env.ts

@@ -38,3 +38,5 @@ export const ongoingEmptyTimeout = parseInt(process.env.ONGOING_EMPTY_TIMEOUT!);
 
 export const TS_BLUE = '#007ACC';
 export const GREEN = '#77b155';
+// Picked from Discord's "hourglass" emoji (in ⌛ | Occupied Help Channels)
+export const HOURGLASS_ORANGE = '#ffa647';

src/modules/helpchan.ts

@@ -12,12 +12,14 @@ import {
 	Guild,
 	TextChannel,
 	GuildMember,
+	User,
 } from 'discord.js';
 import { HelpUser } from '../entities/HelpUser';
 import {
 	categories,
 	TS_BLUE,
 	GREEN,
+	HOURGLASS_ORANGE,
 	askCooldownRoleId,
 	channelNames,
 	dormantChannelTimeout,
@@ -39,6 +41,19 @@ This channel will be dedicated to answering your question only. Others will try
 For more tips, check out StackOverflow's guide on **[asking good questions](https://stackoverflow.com/help/how-to-ask)**.
 `;
 
+const occupiedMessage = (tag: string) => `
+**This channel is claimed by @${tag}**
+
+This channel is dedicated to answering their question only (and any of their follow-up questions). Others will try to answer and help solve the issue.
+
+**To @${tag}, keep in mind:**
+• It's always ok to just ask your question. You don't need permission.
+• Explain what you expect to happen and what actually happens.
+• Include a code sample and error message, if you got any.
+
+For more tips, check out StackOverflow's guide on **[asking good questions](https://stackoverflow.com/help/how-to-ask)**.
+`;
+
 const DORMANT_MESSAGE = `
 This help channel has been marked as **dormant**, and has been moved into the **Help: Dormant** category at the bottom of the channel list. It is no longer possible to send messages in this channel until it becomes available again.
 
@@ -62,6 +77,18 @@ export class HelpChanModule extends Module {
 			} hours of inactivity or when you send !close.`,
 		);
 
+	occupiedEmbed(asker: User) {
+		return new MessageEmbed()
+			.setTitle('⌛ Occupied Help Channel')
+			.setColor(HOURGLASS_ORANGE)
+			.setDescription(occupiedMessage(asker.tag))
+			.setFooter(
+				`Closes after ${
+					dormantChannelTimeout / 60 / 60 / 1000
+				} hours of inactivity or when ${asker.username} sends !close.`,
+			);
+	}
+
 	DORMANT_EMBED = new MessageEmbed()
 		.setColor(TS_BLUE)
 		.setDescription(DORMANT_MESSAGE);