Improved nested object autoediting.

Example:

    Abjad IDE - materials - talea rhythm maker (Bača) ...

       1: talea (t): Talea(counts=(1, 2, 3, 4), denominator=16)
       2: split divisions by counts (sdc):
       3: extra counts per division (xcd):
       4: beam specifier (bs):
       5: burnish specifier (rs):
       6: duration spelling specifier (dss):
       7: tie specifier (ts):

    ... talea (EDIT)

       1: counts (c): (1, 2, 3, 4)
       2: denominator (d): 16

          done (done)
          none (none)

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