panic: 'attempt to subtract with overflow'

[rmcgibbo]

Describe the bug
Formatting a cell containing some unicode escape characters causes a panic

To Reproduce

fn main() {
    use stybulate::{Cell, Table, Style};
    //let s = "foo \u{1b} bar";
    let s = "\u{1b}";
    let v = vec![vec![
        Cell::from(s),
    ]];
    let result = Table::new(
        Style::Plain,
        v,
        None,
    )
    .tabulate();
}

Fails with

thread 'main' panicked at 'attempt to subtract with overflow', /home/mcgibbon/.cargo/registry/src/github.com-1ecc6299db9ec823/stybulate-1.1.2/src/lib.rs:368:21
stack backtrace:
   0: rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::panicking::panic
   3: stybulate::format_unstylable
             at /home/mcgibbon/.cargo/registry/src/github.com-1ecc6299db9ec823/stybulate-1.1.2/src/lib.rs:368:21
   4: stybulate::create_data_lines::{{closure}}
             at /home/mcgibbon/.cargo/registry/src/github.com-1ecc6299db9ec823/stybulate-1.1.2/src/lib.rs:421:17
   5: core::iter::adapters::map::map_fold::{{closure}}
             at /build/rustc-1.58.1-src/library/core/src/iter/adapters/map.rs:84:28
   6: <core::iter::adapters::enumerate::Enumerate<I> as core::iter::traits::iterator::Iterator>::fold::enumerate::{{closure}}
             at /build/rustc-1.58.1-src/library/core/src/iter/adapters/enumerate.rs:106:27
   7: core::iter::traits::iterator::Iterator::fold
             at /build/rustc-1.58.1-src/library/core/src/iter/traits/iterator.rs:2171:21
   8: <core::iter::adapters::enumerate::Enumerate<I> as core::iter::traits::iterator::Iterator>::fold
             at /build/rustc-1.58.1-src/library/core/src/iter/adapters/enumerate.rs:112:9
   9: <core::iter::adapters::map::Map<I,F> as core::iter::traits::iterator::Iterator>::fold
             at /build/rustc-1.58.1-src/library/core/src/iter/adapters/map.rs:124:9
  10: core::iter::traits::iterator::Iterator::for_each
             at /build/rustc-1.58.1-src/library/core/src/iter/traits/iterator.rs:737:9
  11: <alloc::vec::Vec<T,A> as alloc::vec::spec_extend::SpecExtend<T,I>>::spec_extend
             at /build/rustc-1.58.1-src/library/alloc/src/vec/spec_extend.rs:40:17
  12: <alloc::vec::Vec<T> as alloc::vec::spec_from_iter_nested::SpecFromIterNested<T,I>>::from_iter
             at /build/rustc-1.58.1-src/library/alloc/src/vec/spec_from_iter_nested.rs:56:9
  13: <alloc::vec::Vec<T> as alloc::vec::spec_from_iter::SpecFromIter<T,I>>::from_iter
             at /build/rustc-1.58.1-src/library/alloc/src/vec/spec_from_iter.rs:33:9
  14: <alloc::vec::Vec<T> as core::iter::traits::collect::FromIterator<T>>::from_iter
             at /build/rustc-1.58.1-src/library/alloc/src/vec/mod.rs:2549:9
  15: core::iter::traits::iterator::Iterator::collect
             at /build/rustc-1.58.1-src/library/core/src/iter/traits/iterator.rs:1745:9
  16: stybulate::create_data_lines
             at /home/mcgibbon/.cargo/registry/src/github.com-1ecc6299db9ec823/stybulate-1.1.2/src/lib.rs:410:33
  17: stybulate::Table::tabulate
             at /home/mcgibbon/.cargo/registry/src/github.com-1ecc6299db9ec823/stybulate-1.1.2/src/lib.rs:243:25
  18: history::main
             at ./src/main.rs:30:18
  19: core::ops::function::FnOnce::call_once
             at /build/rustc-1.58.1-src/library/core/src/ops/function.rs:227:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

Toolchain: 1.58

[rmcgibbo]

I believe I was able to fix this in my code by running the strings through this before adding them to the table.

fn remove_zero_width_graphemes(s: &str) -> String {
    use unicode_segmentation::UnicodeSegmentation;
    use unicode_width::UnicodeWidthStr;

    UnicodeSegmentation::graphemes(s, true)
        .map(|x| match UnicodeWidthStr::width(x) {
            0 => "",
            _ => x,
        })
        .collect()
}