It was waiting for you to finished the quote. If you type another ' it will complete the quote. You could then try the Home key or Control-A and see if lets you edit the line.
The quotes can be useful when need to give names the shell will try to use, such as:
touch 'Hello There'
Will create a file named "Hello There". Without the ' it will create two files, named Hello and There. It is different than using the " character as:
touch '$HELLO THERE'
Will create a file named "$HELLO THERE", but:
touch "$HELLO THERE"
Will create a file named "THERE" and a file name after the contents of the shell variable $HELLO [assuming it exists].