For Houdini 18.5

From here you can install the add-on manually.

Drop HScript.sublime-package file into Data/Installed Packages

Example:
C:\Users\teared\AppData\Roaming\Sublime Text 3\Installed Packages\HScript.sublime-package

Then follow the rest of the readme, including optional section.

Release 7.1.4

1. Added support for Sublime Text 4:

   https://www.sublimetext.com/blog/articles/sublime-text-4