LTS-5452: shell labels in prose; .exe in the binary note

zsh (macOS default) has interactive_comments off, so pasted '#' lines printed errors; the labels now sit outside the sh fences. The placement note names browserstack-cli.exe for Windows.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: MihirR-BS

README.md

@@ -14,17 +14,17 @@ This repo contains samples for running [WebdriverIO](https://webdriver.io/) test
 
 The BrowserStack CLI reads your credentials from environment variables. Copy your username and access key from [Account Settings](https://www.browserstack.com/accounts/settings) and export them in the shell you run the test from:
 
+On macOS or Linux (bash or zsh), run the lines below. The second one prompts for the key without echoing it, so the key stays out of your shell history:
+
 ```sh
-# macOS / Linux (bash or zsh)
 export BROWSERSTACK_USERNAME="<your-username>"
-# Type the key at the prompt: it is not echoed, and it stays out of your shell history
 printf 'BrowserStack access key: '; read -rs BROWSERSTACK_ACCESS_KEY; echo; export BROWSERSTACK_ACCESS_KEY
 ```
 
+On Windows, run these in PowerShell. The second line prompts for the key in the same way:
+
 ```powershell
-# Windows (PowerShell)
 $env:BROWSERSTACK_USERNAME = "<your-username>"
-# Type the key at the prompt: it is not echoed, and it stays out of your PowerShell history
 $env:BROWSERSTACK_ACCESS_KEY = [System.Net.NetworkCredential]::new('', (Read-Host -AsSecureString 'BrowserStack access key')).Password
 ```