language variant subtag "tongyong" addition request (for Chinese langugaes romanization)

1. Name of requester: Phake Nick
2. E-mail address of requester: [email protected]
3. Record Requested:

Type: variant
Subtag: tongyong
Description: Tongyong Pinyin romanization
Prefix: zh-Latn
Prefix: hak-Latn
Prefix: nan-Latn
Comments: Former official transcription standard for Mandarin Chinese,
Taiwanese Min-Nan, and variant of Hakka language in Taiwan.

4. Intended meaning of the subtag: Indicate Romanized content that use
Tongyong pinyin romanization
5. Reference to published description of the language (book or
article): https://medium.com/@lovenery/%E5%8F%B0%E7%81%A3%E7%9A%84%E6%8B%BC%E9%9F%B3%E5%A4%A7%E6%88%B0-acfe429c071d
(Chinese article on medium, can be read via Google Translate, note
that Google Translate currently translated "Tongyong pinyin" into
"Universal pinyin" and translated "Wade-Giles" into Wittoma/Westin)
6. Any other relevant information: The transcription standard was
official in Taiwan in the mid-2000s. It have now been displaced by
Pinyin romanization as the official transcription rule for Chinese
languages in Taiwan, however it is still continually being used to
certain extent within Taiwan and thus it could/would be helpful to
have a variant subtag to separate it from Pinyin romanization.