InstantCommand

[This link might be helpful](https://first.wpi.edu/wpilib/allwpilib/docs/release/java/edu/wpi/first/wpilibj2/command/InstantCommand.html#:~:text=Class%20InstantCommand&text=A%20Command%20that%20runs%20instantly,subclass%20this%20command%20if%20desired.)

InstantCommands immediately runs and then ends.

Start with the linked WPILib InstantCommand documentation and inspect this repository's wiki or documentation structure to find where the entry belongs. Clarify whether the intended result is a new description or a correction to existing text; done means the repository documents that InstantCommand runs immediately and then ends.

索引モデルが issue の本文から書いたものです。