It looks so bad in the context they give themselves:

C# $"{x} plus {y} equals {x + y}"

Visual Basic $"{x} plus {y} equals {x + y}"

Python f"{x} plus {y} equals {x + y}"

Scala s"$x plus $y equals ${x + y}"

Groovy "$x plus $y equals ${x + y}"

Kotlin "$x plus $y equals ${x + y}"

JavaScript `${x} plus ${y} equals ${x + y}`

Ruby "#{x} plus #{y} equals #{x + y}"

Swift "\(x) plus \(y) equals \(x + y)"

And finally:

Java STR."\{x} plus \{y} equals \{x + y}"