m->d: Strip colons from user mentions

m2d/converters/event-to-message.js

@@ -401,6 +401,10 @@ async function eventToMessage(event, guild, di) {
 				return `${attributeValue} data-channel-id="${channelID}">`
 			})
 
+			// Stripping colons after mentions
+			input = input.replace(/( data-user-id.*?<\/a>):?/g, "$1")
+			input = input.replace(/("https:\/\/matrix.to.*?<\/a>):?/g, "$1")
+
 			// Element adds a bunch of <br> before </blockquote> but doesn't render them. I can't figure out how this even works in the browser, so let's just delete those.
 			input = input.replace(/(?:\n|<br ?\/?>\s*)*<\/blockquote>/g, "</blockquote>")
 

m2d/converters/event-to-message.test.js

@@ -1556,7 +1556,7 @@ test("event2message: mentioning discord users works", async t => {
 				msgtype: "m.text",
 				body: "wrong body",
 				format: "org.matrix.custom.html",
-				formatted_body: `I'm just <a href="https://matrix.to/#/@_ooye_extremity:cadence.moe">▲</a> testing mentions`
+				formatted_body: `I'm just <a href="https://matrix.to/#/@_ooye_extremity:cadence.moe">extremity</a> testing mentions`
 			},
 			event_id: "$g07oYSZFWBkxohNEfywldwgcWj1hbhDzQ1sBAKvqOOU",
 			origin_server_ts: 1688301929913,
@@ -1639,6 +1639,36 @@ test("event2message: mentioning bridged rooms works", async t => {
 	)
 })
 
+test("event2message: colon after mentions is stripped", async t => {
+	t.deepEqual(
+		await eventToMessage({
+			content: {
+				msgtype: "m.text",
+				body: "wrong body",
+				format: "org.matrix.custom.html",
+				formatted_body: `<a href="https://matrix.to/#/@_ooye_extremity:cadence.moe">extremity</a>: hey, I'm just <a href="https://matrix.to/#/@rnl:cadence.moe">▲</a>: testing mentions`
+			},
+			event_id: "$g07oYSZFWBkxohNEfywldwgcWj1hbhDzQ1sBAKvqOOU",
+			origin_server_ts: 1688301929913,
+			room_id: "!kLRqKKUQXcibIMtOpl:cadence.moe",
+			sender: "@cadence:cadence.moe",
+			type: "m.room.message",
+			unsigned: {
+				age: 405299
+			}
+		}),
+		{
+			messagesToDelete: [],
+			messagesToEdit: [],
+			messagesToSend: [{
+				username: "cadence [they]",
+				content: "<@114147806469554185> hey, I'm just [▲](<https://matrix.to/#/@rnl:cadence.moe>) testing mentions",
+				avatar_url: undefined
+			}]
+		}
+	)
+})
+
 test("event2message: caches the member if the member is not known", async t => {
 	let called = 0
 	t.deepEqual(