docs: explain more clearly why it was bad

Author: vohoanglong0107

clippy_lints/src/methods/mod.rs

@@ -3973,11 +3973,15 @@ declare_clippy_lint! {
 
 declare_clippy_lint! {
     /// ### What it does
-    /// Checks for unnecessary calls to `min()` or `max()`
+    /// Checks for unnecessary calls to `min()` or `max()` in the following cases
+    /// - Either both side is constant
+    /// - One side is clearly larger than the other, like i32::MIN and an i32 variable
     ///
     /// ### Why is this bad?
     ///
-    /// In these cases it is not necessary to call `min()`
+    /// In the aformentioned cases it is not necessary to call `min()` or `max()`
+    /// to compare values, it may even cause confusion.
+    ///
     /// ### Example
     /// ```no_run
     /// let _ = 0.min(7_u32);