fix: correctly name keymap for change_line

[merlinio2000]

This caused me a bug where the keymap for change would be disabled when configuring change_line = false

The bug occurs because of the logic in set_keymap

    -- If the keymap is disabled
    if not args.lhs then
        -- If the mapping is disabled globally, do nothing
        if not M.user_opts.keymaps[args.name] then
            return
        end
        -- Otherwise disable the global keymap
        args.lhs = M.user_opts.keymaps[args.name]
        args.rhs = "<NOP>"
    end
    vim.keymap.set(args.mode, args.lhs, args.rhs, args.opts)

Entering this function for change_line we get lhs = false (correct) but since name = "change" (incorrect) it thinks that the mapping is not globally disabled so it overrides the lhs for change with "<NOP>"

The problem is resolved by correctly giving the change_line keymap its own name (like visual_line etc. already do)