Just clarifies a little the bun installation process and gives people…

… instructions what to do if it did not install.

guides/source/working_with_javascript_in_rails.md

@@ -94,7 +94,7 @@ Bun, then you just need to install Bun as it is both a JavaScript runtime and a
 #### Installing Bun
 
 Find the installation instructions at the [Bun website](https://bun.sh) and
-verify it’s installed correctly with the following command:
+verify it’s installed correctly and in your path with the following command:
 
 ```bash
 $ bun --version
@@ -103,6 +103,8 @@ $ bun --version
 The version of your Bun runtime should be printed out. If it says something
 like `1.0.0`, Bun has been installed correctly.
 
+If not, you may need to reinstall bun in the current directory or restart your terminal.
+
 #### Installing Node.js and Yarn
 
 If you are using esbuild, rollup.js or Webpack you will need Node.js and Yarn.