gulp: Fixed changes task

This fixes an issue in the changes task where removed languages were
causing a property access on `undefined`.

gulpfile.js/changelog.js

@@ -105,7 +105,7 @@ const revisionRanges = {
 const strCompare = (a, b) => a.localeCompare(b, 'en');
 
 async function changes() {
-	const { languages, plugins } = require('../components');
+	const { languages, plugins } = require('../components.js');
 
 	const infos = await getLog(revisionRanges.nextRelease);
 
@@ -225,9 +225,12 @@ async function changes() {
 					const change = relevantChanges[0];
 					if (change.mode === 'A' && change.file.startsWith('components/prism-')) {
 						const lang = change.file.match(/prism-([\w-]+)\.js$/)[1];
-						const titles = [languages[lang].title];
-						if (languages[lang].aliasTitles) {
-							titles.push(...Object.values(languages[lang].aliasTitles));
+						const entry = languages[lang] || {
+							title: "REMOVED LANGUAGE " + lang,
+						};
+						const titles = [entry.title];
+						if (entry.aliasTitles) {
+							titles.push(...Object.values(entry.aliasTitles));
 						}
 						addEntry('New components', `__${titles.join('__ & __')}__: ${infoToString(info)}`);
 						return true;