fix(dial): Fix dial.nvim commands in visual line/block

[grddavies]

In the dial.nvim extra config, keymaps use the dial normal mode commands in visual line and visual block mode.

This limits the cases where the dial.nvim keymaps can be used. Eg visual-block selecting and incrementing all object keys to fix this example:

const digitToStr = {
  //   < v-block  ctrl-a >
  one: "0",
  two: "1",
  three: "2",
  // ...
};

This PR fixes the mode argument passed to the dial.manipulate function when using <C-a>, <C-x>, g<C-a> and g<C-x> when in VISUAL-LINE and VISUAL-BLOCK modes.

[folke]

Thanks!