Repository: yt-dlp
Issue: PBS additional metadata available to capture
Labels: site-enhancement

### Checklist

- [X] I'm reporting a site feature request
- [X] I've verified that I'm running yt-dlp version **2022.04.08** ([update instructions](https://github.com/yt-dlp/yt-dlp#update)) or later (specify commit)
- [X] I've checked that all provided URLs are alive and playable in a browser
- [X] I've searched the [bugtracker](https://github.com/yt-dlp/yt-dlp/issues?q=) for similar issues including closed ones. DO NOT post duplicates
- [X] I've read the [guidelines for opening an issue](https://github.com/yt-dlp/yt-dlp/blob/master/CONTRIBUTING.md#opening-an-issue)
- [X] I've read about [sharing account credentials](https://github.com/yt-dlp/yt-dlp/blob/master/CONTRIBUTING.md#are-you-willing-to-share-account-details-if-needed) and I'm willing to share it if required

### Region

United States

### Example URLs

https://www.pbs.org/video/dptv-documentaries-detroit-remember-when-made-motor-city/

### Description

When embedding metadata with PBS videos, the long description, airdate, and rating ought to be included.

The information is conveniently found all together in the page source. 
```
<script type="[application/ld+json]()">
{
  "@context" : "https://schema.org",
  "@type" : "VideoObject",
  "name" : "Detroit Remember When: Made in the Motor City",
  "contentRating" : "NR",
  "datePublished" : "2015-03-05T18:21:27Z",
  "description" : "Narrated by broadcast legend, Erik Smith, and through the lens of filmmaker Bill Kubota, the documentary will take viewers cruising through the Woodward Gratiot automotive corridor, dining at American Coney Island and Buddy’s Pizza, while listening to the voices of famous Detroit personalities such as Jo-Jo Shutty McGregor, Ken Calvert and many more!",

```

Suggested mapping:
"description" string >> "long description" atom
"datePublished" string >> "year" atom (in full UTC form)
"contentRating" string >> "rating" atom


### Verbose log

```shell
[debug] Command-line config: ['-vU', '-f', '[protocol^=http]', '--write-all-thumbnails', '--write-info-json', '--write-subs', '--sub-langs', 'en.*', '--write-description', '--write-info-json', '--write-playlist-metafiles', '--write-comments', '--abort-on-unavailable-fragment', '-o', '%(title)s\\%(title)s.%(ext)s', 'https://www.pbs.org/video/dptv-documentaries-detroit-remember-when-made-motor-city/']
[debug] Encodings: locale cp1252, fs utf-8, out utf-8, err utf-8, pref cp1252
[debug] yt-dlp version 2022.04.08 [7884ade] (win_exe)
[debug] Python version 3.8.10 (CPython 64bit) - Windows-10-10.0.22581-SP0
[debug] Checking exe version: ffmpeg -bsfs
[debug] Checking exe version: ffprobe -bsfs
[debug] exe versions: ffmpeg 5.0.1-full_build-www.gyan.dev (setts), ffprobe 5.0.1-full_build-www.gyan.dev, rtmpdump 2.3
[debug] Optional libraries: brotli, certifi, Cryptodome, mutagen, sqlite, websockets
[debug] Proxy map: {}
Latest version: 2022.04.08, Current version: 2022.04.08
yt-dlp is up to date (2022.04.08)
[debug] Using fake IP 6.71.149.112 (US) as X-Forwarded-For
[pbs] Downloading JSON metadata
[debug] [pbs] Extracting URL: https://www.pbs.org/video/dptv-documentaries-detroit-remember-when-made-motor-city/
[pbs] dptv-documentaries-detroit-remember-when-made-motor-city: Downloading webpage
[pbs] dptv-documentaries-detroit-remember-when-made-motor-city: Downloading widget/partnerplayer page
[pbs] dptv-documentaries-detroit-remember-when-made-motor-city: Downloading portalplayer page
[pbs] dptv-documentaries-detroit-remember-when-made-motor-city: Downloading 0 video url info
[pbs] dptv-documentaries-detroit-remember-when-made-motor-city: Downloading m3u8 information
[pbs] dptv-documentaries-detroit-remember-when-made-motor-city: Downloading 1 video url info
[debug] Formats sorted by: hasvid, ie_pref, lang, quality, res, fps, hdr:12(7), vcodec:vp9.2(10), acodec, filesize, fs_approx, tbr, vbr, abr, asr, proto, vext, aext, hasaud, source, id
[debug] Downloading subtitles: en
[info] 2365438277: Downloading 1 format(s): 1
[info] Writing video description to: DPTV Documentaries - Detroit Remember When - Made in the Motor City\DPTV Documentaries - Detroit Remember When - Made in the Motor City.description
[info] Writing video subtitles to: DPTV Documentaries - Detroit Remember When - Made in the Motor City\DPTV Documentaries - Detroit Remember When - Made in the Motor City.en.vtt
[debug] Invoking downloader on "https://ga.video.cdn.pbs.org/videos/dptv-documentaries/87239ce2-b947-4561-bb6d-818a38718522/174377/hd-mezzanine-16x9/485c11a3_madeinthemotorcitypledge-captions_357.m3u8"
[hlsnative] Downloading m3u8 manifest
[hlsnative] Total fragments: 31
[download] Destination: DPTV Documentaries - Detroit Remember When - Made in the Motor City\DPTV Documentaries - Detroit Remember When - Made in the Motor City.en.vtt
[debug] File locking is not supported on this platform. Proceeding without locking
[download] 100% of 95.52KiB in 00:08
[info] Downloading video thumbnail 0 ...
[info] Writing video thumbnail 0 to: DPTV Documentaries - Detroit Remember When - Made in the Motor City\DPTV Documentaries - Detroit Remember When - Made in the Motor City.jpeg
[info] Writing video metadata as JSON to: DPTV Documentaries - Detroit Remember When - Made in the Motor City\DPTV Documentaries - Detroit Remember When - Made in the Motor City.info.json
[debug] Invoking downloader on "https://ga.video.cdn.pbs.org/videos/dptv-documentaries/87239ce2-b947-4561-bb6d-818a38718522/174377/hd-mezzanine-16x9/485c11a3_madeinthemotorcitypledge-16x9-mp4-2500k.mp4"
[download] Destination: DPTV Documentaries - Detroit Remember When - Made in the Motor City\DPTV Documentaries - Detroit Remember When - Made in the Motor City.mp4
[download] 100% of 2.20GiB in 00:49
```