precedence should not warn for unary minus before odd function

The `clippy:precedence` list currently warns on every instance of the form `-literal.method()`, as precedence looks ambiguous. However, for an *odd function*, i.e. a function `f(x)` where `f(-x)=-f(x)`, the precedence doesn't matter. Many functions have this property, such as `sin()`, `atan()`, `cbrt()`, `to_radians()` (and `round()` i think).