Update prompt_regexp for console code examples in guides

For code examples in irb we remove the prompt (`irb>`) from the results
for the copy button. For the following example the result would be `puts
"hello!"`:
```irb
irb> puts "hello!"
```

With the updated console prompt the regexp needs to change to support:
```irb
blog(test)> puts "hello!"
```

Author: p8

guides/rails_guides/markdown/renderer.rb

@@ -88,7 +88,7 @@ def clipboard_content(code, language)
             when "bash"
               /^\$ /
             when "irb"
-              /^irb.*?> /
+              /^(irb.*?|\w+\(\w+\))> /
             end
 
           if prompt_regexp