All the bits of Tree-sitter now landed on Guix master! You can try it out with emacs-next:
guix shell emacs-next tree-sitter-html -- emacs
Open html file, M-x html-ts-mode RET M-x treesit-explore-mode RET.
25 grammars are packaged already, but emacs have smaller number of -ts- modes available ATM.
Thank you everyone for the work!