fix: is-jagged determination patterns miss the brackets

[mrzimu]

Hi,

This PR may be trivial so far, since the regex pattern I modified is for determinating whether a branch is jagged, which the result value is_jagged is never used at present.

I found this mistake when I use _from_leaves_one to check whether a branch is jagged or not in uproot-custom, and I think I might as well fix this bug now.

My understanding to these patterns is that, when a branch contains arrays, there will be [dim1][dim2]... patterns in title. As long as dimx is not an integer, the branch is jagged.

Expected behavior:

1. Use _item_any_pattern to find all strings matching the [xxx] pattern.
2. Use _item_dim_pattern to check if xxx is an integer. If not, set is_jagged to True.

Actual behavior (before fixing):

1. _item_any_pattern captures all [xxx]-like strings but discards the brackets, only retaining xxx.
2. _item_dim_pattern requires the full [xxx] pattern to validate xxx, but since the brackets are already missed, the input xxx can never satisfy this pattern.

[ariostas]

Thank you @mrzimu, you're right!

I was hoping that this might also fix #1498, but it seems like it's a separate thing.

[ianna]

@mrzimu - great ! thanks for fixing it!

[mrzimu]

Thank you @mrzimu, you're right!

I was hoping that this might also fix #1498, but it seems like it's a separate thing.

It doesn't fix #1498, but they should be a little relevant I guess:

#1498 (comment)

[mrzimu]

And I have no idea why the pipeline failed...

[ariostas]

Don't worry about it, it's not your fault. I already fixed it in another PR.