Squiggly lines included with output within console

Why does it include the squiggly lines when I run this code under the console?

Repl link:

greet = 'hi ${name}, Nice to meet you!'
  greeting('Amber Heard')

Unnecessary curly brace and an undefined function. Remove it and the “squiggly line” (syntax error) will go away.

So, why can the Clever Programmer guy use squiggly lines and not get them in his output? I am following his video here at 51 minutes into the video.

what is a squiggly line? {? That’s a curly brace. The reason he’s not getting errors is because you didn’t even type the code correctly.