YAML syntax highlighting not working

[joschaschmiedt]

Steps to reproduce

1. Create a yaml file, e.g.

 doe: "a deer, a female deer"
 ray: "a drop of golden sun"
 pi: 3.14159
 xmas: true
 french-hens: 3
 calling-birds:
   - huey
   - dewey
   - louie
   - fred

Expected behaviour

Syntax highlighting should be visible, similar to JSON.

Actual behaviour

All text remains black

Server configuration

Operating system:
Linux 4.19.0-14-amd64 x86_64

Web server:

Database:
type: mysql
Version: 10.3.27
Size: 2.6 MB

PHP version:

Version: 7.3.27
Memory Limit: 2 GB
Max Execution Time: 3600
Upload max size: 1 GB

Nextcloud version:
21.0.4

[joschaschmiedt]

Could this be due to the fact that https://github.com/nextcloud/files_texteditor/blob/master/js/SyntaxMode.js doesn't actually contain code for YAML? YAML is listed in https://github.com/nextcloud/files_texteditor/blob/master/js/supported_mimetypes.json though.