Make code snippet executable when using copy button (#193)

The code snippets have a copy button on the far right side of the 'code area'.
But when you paste the copied text into your terminal, the copied text is not executable: it has a dollar sign in the front. On the web page, it signifies the user's prompt, but in the terminal, the shell can't make any chocolate of it ;-)

So in order to facilitate the users that want to copy the code examples into their terminal windows, this PR proposes to remove the leading $-sign in the code snippets. And maybe you know something smart for multi-line snippets as well (rewrite using && perhaps?).

README.md

@@ -11,7 +11,7 @@ See the [New Clojure project quickstart](https://blog.michielborkent.nl/new-cloj
 ### Homebrew (Linux and macOS)
 
 ```
-$ brew install babashka/brew/neil
+brew install babashka/brew/neil
 ```
 
 ### Scoop (Windows)