Reformat panic reasons into a list

Author: LFS6502

library/alloc/src/vec/mod.rs

@@ -3028,10 +3028,10 @@ impl<T: Clone, A: Allocator> Vec<T, A> {
     /// Copies elements from one part of the vector to the end.
     /// `src` is the range that the elements will be copied from.
     ///
-    /// # Panics
+    /// # Panics if:
     ///
-    /// Panics if the starting index is greater than the end index.
-    /// Panics if the end index is greater than the length of the vector.
+    /// - Panics if the starting index is greater than the end index.
+    /// - Panics if the end index is greater than the length of the vector.
     ///
     /// # Examples
     ///