refacto/feat: better handling of parser updates

features:
- node_movement is moving between scopes.
- add selection initialization from normal mode
- add a decremental selection

improvements:
- attach to buffer to run tree parsing on change
- run state update on CursorMoved
- the buffer state is:
```
{
  cursor_pos = { row=row, col=col },
  current_node = node_under_cursor,
  selection = {
      range = nil, -- activates when starting a selection
      nodes = {} -- filling up when starting an incremental selection
  },
  parser = parser, -- parser for current buffer
}
```
- refacto all the modules reliant on parsing the tree, update the current nodes, get the current nodes...

fixes:
- fix has_parser to look for .so libraries
- fix should select the whole file when selection root in selection

lua/nvim-treesitter/highlight.lua

@@ -1,5 +1,6 @@
 local api = vim.api
 local ts = vim.treesitter
+
 local queries = require'nvim-treesitter.query'
 
 local M = {