Markdown highlight injection matches on substring, not only full text

[aster-void]

Summary

I expect this to only match js and not any string that contains string "js"

Reproduction Steps

I tried this:

1. nix run github:helix-editor/helix highlight.md
2. write the text in the screenshot

I expected this to happen:

fooba_bazjs doesn't highlight

Instead, this happened:

helix highlighted it as javascript

Helix log

~/.cache/helix/helix.log

please provide a copy of `~/.cache/helix/helix.log` here if possible, you may need to redact some of the lines

Platform

Linux

Terminal Emulator

kitty 0.40.0 created by Kovid Goyal

Installation Method

runned the flake directly

Helix Version

helix 25.01.1 (13b2dc3)