change mapping into function-based interface

[monaqa]

This PR changes require("dial.map").inc_normal and others into function, which enables us to set group_name dynamically.

• support dot repeating
• support [count]
• update document

To support count, maybe we have to break the existing interface.

[leiserfg]

Maybe you can use vim.v.count1 to get the count in the function and pass it somehow?

[leiserfg]

The count works fine for . like 3<c-a> does not add only once but then 2. works fine, I will try to find why so we can merge this after.

[leiserfg]

Hi @monaq any way I can help to get this merged?

[monaqa]

Thanks. I am currently considering what procedure would be preferable for the merge.
It is a kind of breaking change, and I want to reduce the impact on users as much as possible.

[monaqa]

To avoid breaking changes, instead of modifying the inc_normal function and others, a new function manipulate was added to support the functional interface.

[leiserfg]

Was the removal of apply_if_function intentional?

[monaqa]

Yes, I have decided it is not necessary because the evaluation of group_name can be delayed by the following:

vim.keymap.set("n", "<C-a>", function()
    local group_name = evaluate_some_expr()
    require("dial.map").manipulate("increment", "normal", group_name)
end)