RUF031 fix should ensure that a parenthesized single-element tuple has a comma

[dscorbett]

Description

The fix for incorrectly-parenthesized-tuple-in-subscript (RUF031) in Ruff 0.9.6 produces a syntax error when it tries to insert parentheses around a starred expression with no comma.

$ cat >ruf031.py <<'# EOF'
x[*y]
# EOF

$ ruff --isolated check --preview --select RUF031 ruf031.py --config 'lint.ruff.parenthesize-tuple-in-subscript = true' --diff 2>&1 | grep error:
error: Fix introduced a syntax error. Reverting all changes.

The correct fix would be to insert a comma along with the parentheses:

x[(*y,)]

[dylwil3]

I think that even if the user selects true for parenthesize-tuple-in-subscript we should keep this as x[*y] (just for tuples of size one that are starred like this). It feels like the parenthesization in that case hurts readability in a way probably not intended.