Improve magic-value-comparison example in docs (#8111)

Closes https://github.com/astral-sh/ruff/issues/8109.

crates/ruff_linter/src/rules/pylint/rules/magic_value_comparison.rs

@@ -22,17 +22,23 @@ use crate::rules::pylint::settings::ConstantType;
 ///
 /// ## Example
 /// ```python
-/// def calculate_discount(price: float) -> float:
-///     return price * (1 - 0.2)
+/// def apply_discount(price: float) -> float:
+///     if price <= 100:
+///         return price / 2
+///     else:
+///         return price
 /// ```
 ///
 /// Use instead:
 /// ```python
-/// DISCOUNT_RATE = 0.2
+/// MAX_DISCOUNT = 100
 ///
 ///
-/// def calculate_discount(price: float) -> float:
-///     return price * (1 - DISCOUNT_RATE)
+/// def apply_discount(price: float) -> float:
+///     if price <= MAX_DISCOUNT:
+///         return price / 2
+///     else:
+///         return price
 /// ```
 ///
 /// [PEP 8]: https://peps.python.org/pep-0008/#constants