Use the correct unicode checkmark symbol in success messages

[Infinoid]

✓ is U+2713, check mark. √ is U+221A, square root (radical symbol).

[Infinoid]

Note that if you don't like the look of a normal check mark, there are some other options available as well. Wikipedia has a list. And there's also the thumbs up symbol.

I just don't like the use of the square root symbol for this, my eyes always try to read it as a math equation.