You can make it open res files in ReScript lang by adding this to your config, afaik it’s a limitation in Zed now, extensions don’t get to configure this from what I’ve seen so far:
"file_types": {
"ReScript": ["res", "resi"]
}
In terms of debugging or even compiling locally, follow the README here: GitHub - humaans/rescript-zed: ReScript support for Zed editor. You can see the LSP output by Cmd + shift + p and
debug: open language server logs