chore(lang): update zh-TW translations (videojs#8929)

## Description
- Add "Playing in Picture-in-Picture" translations to zh-TW.json
- Deduplicate object keys in zh-TW.json
- Update translations-needed.md
- Auto-generated - The np.json section removed from
translations-needed.md was a duplicate.

## Specific Changes proposed
- Add missing translation for "Playing in Picture-in-Picture" to zh-TW
locale.
- Remove duplicate keys 'Picture-in-Picture' and 'Exit
Picture-in-Picture' from zh-TW.json to eliminate redundancy.

## Requirements Checklist
- [ ] Feature implemented / Bug fixed
- [ ] If necessary, more likely in a feature request than a bug fix
- [x] Change has been verified in an actual browser (Chrome, Firefox,
IE)
  - [x] Docs/guides updated
- [x] Has no DOM changes which impact accessiblilty or trigger warnings
(e.g. Chrome issues tab)
  - [x] Has no changes to JSDoc which cause `npm run docs:api` to error
- [ ] Example created ([starter template on
JSBin](https://codepen.io/gkatsev/pen/GwZegv?editors=1000#0))
- [ ] Reviewed by Two Core Contributors

---------

Co-authored-by: Harisha Rajam Swaminathan <[email protected]>

Author: SimonAllen0901

docs/translations-needed.md

@@ -16,7 +16,7 @@ This default value is hardcoded as a default to the localize method in the SeekB
 
 | Language file           | Missing translations                                                                |
 | ----------------------- | ----------------------------------------------------------------------------------- |
-| ar.json (Complete)     |                                                       |
+| ar.json (Complete)      |                                                                                     |
 | az.json (Complete)      |                                                                                     |
 | ba.json (missing 71)    | Audio Player                                                                        |
 |                         | Video Player                                                                        |
@@ -506,6 +506,7 @@ This default value is hardcoded as a default to the localize method in the SeekB
 |                         | Text Background                                                                     |
 |                         | Caption Area Background                                                             |
 |                         | Playing in Picture-in-Picture                                                       |
+| mr.json (Complete)      |                                                                                     |
 | nb.json (Complete)      |                                                                                     |
 | nl.json (missing 1)     | Playing in Picture-in-Picture                                                       |
 | nn.json (missing 10)    | Exit Picture-in-Picture                                                             |
@@ -527,15 +528,6 @@ This default value is hardcoded as a default to the localize method in the SeekB
 |                         | Playing in Picture-in-Picture                                                       |
 |                         | Skip backward {1} seconds                                                           |
 |                         | Skip forward {1} seconds                                                            |
-| np.json (missing 9)     | Drop shadow                                                                         |
-|                         | No content                                                                          |
-|                         | Color                                                                               |
-|                         | Opacity                                                                             |
-|                         | Text Background                                                                     |
-|                         | Caption Area Background                                                             |
-|                         | Playing in Picture-in-Picture                                                       |
-|                         | Skip backward {1} seconds                                                           |
-|                         | Skip forward {1} seconds                                                            |
 | oc.json (missing 7)     | Color                                                                               |
 |                         | Opacity                                                                             |
 |                         | Text Background                                                                     |
@@ -790,6 +782,6 @@ This default value is hardcoded as a default to the localize method in the SeekB
 |                         | Skip forward {1} seconds                                                            |
 | zh-CN.json (missing 2)  | Drop shadow                                                                         |
 |                         | Playing in Picture-in-Picture                                                       |
-| zh-TW.json (missing 1)  | Playing in Picture-in-Picture                                                       |
+| zh-TW.json (Complete)   |                                                                                     |
 
 <!-- END langtable -->

lang/zh-TW.json

@@ -10,8 +10,6 @@
   "Progress": "進度",
   "Fullscreen": "全螢幕",
   "Exit Fullscreen": "退出全螢幕",
-  "Picture-in-Picture": "子母畫面",
-  "Exit Picture-in-Picture": "退出子母畫面",
   "Mute": "靜音",
   "Unmute": "開啟音效",
   "Playback Rate": " 播放速率",
@@ -87,6 +85,7 @@
   "progress bar timing: currentTime={1} duration={2}": "{1}/{2}",
   "{1} is loading.": "{1} 正在載入。",
   "Exit Picture-in-Picture": "離開子母畫面",
+  "Playing in Picture-in-Picture": "在子母畫面中播放",
   "Picture-in-Picture": "子母畫面",
   "No content": "沒有內容",
   "Color": "顏色",