Convert 12 JavaScript files to TypeScript (#57575)

src/content-render/unified/text-only.ts

@@ -7,11 +7,12 @@ import { decode } from 'html-entities'
 // Take advantage of the subtle fact that a lot of the times, the html value
 // we get here is a single line that starts with `<p>` and ends with `</p>`
 // and contains no longer HTML tags.
-export function fastTextOnly(html) {
+export function fastTextOnly(html: string): string {
   if (!html) return ''
   if (html.startsWith('<p>') && html.endsWith('</p>')) {
     const middle = html.slice(3, -4)
     if (!middle.includes('<')) return decode(middle.trim())
   }
-  return cheerio.load(html, { xmlMode: true }).text().trim()
+  const $ = cheerio.load(html, { xmlMode: true })
+  return $.root().text().trim()
 }