[Feature] Add 'hijack_cursor' option from nvim-tree

[hernancerm]

The plugin nvim-tree has the option nvim-tree.hijack_cursor which is documented as follows:

*nvim-tree.hijack_cursor*
Keeps the cursor on the first letter of the filename when moving in the tree.
  Type: `boolean`, Default: `false`

I think having that feature in this plugin would be nice for user experience. Basically, when moving the cursor among the symbols using j and k, the cursor would be positioned in the first character of the symbol name.

Demo of 'hijack_cursor' option in nvim-tree (only j and k are used to navigate)