List.removeLast() docs error occurs if empty

Seems like this should be explicitly stated in the docs. I did not indicate the specific type of error because of #26087.

Closes #35894
#35894

GitOrigin-RevId: 271ab85
Change-Id: I0ab38116dfa63046a433ea59470a1bfe279b98a2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/107822
Reviewed-by: Lasse R.H. Nielsen <[email protected]>
Commit-Queue: Lasse R.H. Nielsen <[email protected]>

Author: camsteffen

sdk/lib/core/list.dart

@@ -537,6 +537,8 @@ abstract class List<E> implements EfficientLengthIterable<E> {
   /**
    * Pops and returns the last object in this list.
    *
+   * The list must not be empty.
+   *
    * Throws an [UnsupportedError] if this is a fixed-length list.
    */
   E removeLast();