Wrong checksum glyph

[hallsbyra]

Encoding 1hnL9wrba2JYA3xxYGGcGq results in Ì1hnL9wrba2JYA3xxYGGcGq Î, when it ought to be Ì1hnL9wrba2JYA3xxYGGcGqÂÎ.

Repro:

describe('Code128Encoder', () => {
    const code128Encoder = new Code128Encoder()

    it('encodes a problematic ID', () => {
        const encoded = code128Encoder.encode('1hnL9wrba2JYA3xxYGGcGq', { output: 'ascii' as any })
        expect(encoded).toBe('Ì1hnL9wrba2JYA3xxYGGcGqÂÎ')
    })
})