syntax for beginning and ending a diff command is:
"new_diff_command" -> "apply_diff_command"
syntax for applying a diff_command is:
"_as_commit" : Begins and Commits a standalone undo Command
"_as_subcommand" : adds to undo but does not Begin or Commit a Command
"_only" : (new) applies the note_diff but does not have any effect on undo
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