[commands] Add withDeadline modifier (#7299)

Co-authored-by: Ryan Blue <ryanzblue@gmail.com>

wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/Command.java

@@ -287,6 +287,24 @@ public abstract class Command implements Sendable {
     return group;
   }
 
+  /**
+   * Creates a new command that runs this command and the deadline in parallel, finishing (and
+   * interrupting this command) when the deadline finishes.
+   *
+   * <p>Note: This decorator works by adding this command to a composition. The command the
+   * decorator was called on cannot be scheduled independently or be added to a different
+   * composition (namely, decorators), unless it is manually cleared from the list of composed
+   * commands with {@link CommandScheduler#removeComposedCommand(Command)}. The command composition
+   * returned from this method can be further decorated without issue.
+   *
+   * @param deadline the deadline of the command group
+   * @return the decorated command
+   * @see Command#deadlineFor
+   */
+  public ParallelDeadlineGroup withDeadline(Command deadline) {
+    return new ParallelDeadlineGroup(deadline, this);
+  }
+
   /**
    * Decorates this command with a set of commands to run parallel to it, ending when the calling
    * command ends and interrupting all the others. Often more convenient/less-verbose than
@@ -321,6 +339,7 @@ public abstract class Command implements Sendable {
    * @param parallel the commands to run in parallel. Note the parallel commands will be interrupted
    *     when the deadline command ends
    * @return the decorated command
+   * @see Command#withDeadline
    */
   public ParallelDeadlineGroup deadlineFor(Command... parallel) {
     return new ParallelDeadlineGroup(this, parallel);