docs(readme): mention wasmtime_home (bytecodealliance#9394)

README.md

@@ -34,6 +34,7 @@ script:
 ```sh
 curl https://wasmtime.dev/install.sh -sSf | bash
 ```
+This script installs into `$WASMTIME_HOME` (defaults to `$HOME/.wasmtime`), and executable is placed in `$WASMTIME_HOME/bin`.
 
 Windows or otherwise interested users can download installers and
 binaries directly from the [GitHub