doc:   [
    DocGroup({"tag": "h3"}, [
        DocChars("12345")
    ]),
    DocGroup({"tag": "h3"}, [
        DocChars("$")
    ]),
]

a_del: [
    DelGroup([
        DelSkip(5)
    ]),
    DelWithGroup([
        DelSkip(1),
    ]),
]
a_add: [
    AddGroup({"tag": "h3"}, [
        AddSkip(5)
    ]),
    AddWithGroup([
        AddChars("-"),
        AddSkip(1),
    ]),
]

b_del: [
    DelGroup([
        DelSkip(5)
    ]),
    DelGroup([
        DelChars(1),
    ])
]
b_add: [
    AddGroup({"tag": "h3"}, [
        AddSkip(5),
    ])
]