Relay VSCode Extension: Does not work without Watchman

Hi all!

When trying to use the VSCode Extension, I'm greeted with the following errors:
```
/workplace/xxx/YYYY/node_modules/relay-compiler/linux-x64/r
elay --watch --output=verbose
thread 'main' panicked at 'Cannot run relay in watch mode if `watchman` is not available (or explicitly disabled).', crates/relay-bin/src/main.rs:286:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
```

This could be a misunderstanding of the requirements (i.e. watchman is actually a required implicit dependency).

If so, some follow-ups:
1. Neither the documentation of the extension nor the Relay docs - which links to it - mentions this as a dependency. It would be great if this could be noted for fellow travelers.
2. It is effectively impossible to install watchman on certain platforms (see https://github.com/facebook/watchman/issues/1135). Are there plans to remove the dependency on watchman to allow wider usage of the extension? It seems this has been done for `vscode-graphql` in https://github.com/graphql/vscode-graphql/issues/116, however here the dependency seems deeper.
3. In the meantime, are there recommended alternative IDE (VS Code) toolings to use for Relay development? Presumably before Relay 14.x - which is a requirement for the Relay VSCode extension, Relay users used other tools for syntax highlighting, autocomplete, etc. Should those still work with Relay 14.x?

(Apologies if I missed that *one thing, and it is actually possible to use the Relay VSCode extension without watchman)

Many thanks!