fix incorrect suggestion in `suboptimal_flops`
fixes#10003
There was an error when trying to negate an expression like `x - 1.0`. We used to format it as `-x - 1.0` whereas a proper negation would be `-(x - 1.0)`.
Therefore, we add parentheses around the expression when it is `ExprKind::Binary`.
We also add parentheses around multiply and divide expressions, even though this is not strictly necessary.
changelog: [`suboptimal_flops`]: fix incorrect suggestion caused by an incorrect negation of floating point expressions.