Fix escaping in @round

Author: dpsanders

src/intervals/rounding_macros.jl

@@ -22,7 +22,7 @@ function round_expr(ex::Expr, rounding_mode::RoundingMode)
             return :( $(esc(op))( $(esc(ex.args[2])), $(esc(ex.args[3])), $rounding_mode) )
 
         else  # unary operator
-            return :( $op($(esc(ex.args[2])), $rounding_mode ) )
+            return :( $(esc(op))($(esc(ex.args[2])), $rounding_mode ) )
         end
     else
         return ex