Fix incremental selection (#1135)

So, there are two problems:

- There was an infinite loop when inc selection was initiated
  from an injection.
- The comparison was wrong when the whole file was selected,
  this is because ts matches the EOF.
  This is an extra line with one char (EOF).

I put a workaround to try to select the node from the main
tree, but we should try to select the node from the parent tree of the
injection, but I wasn't able to get the parent tree from the node.

lua/nvim-treesitter/incremental_selection.lua

@@ -22,11 +22,32 @@ end
 local function visual_selection_range()
   local _, csrow, cscol, _ = unpack(vim.fn.getpos("'<"))
   local _, cerow, cecol, _ = unpack(vim.fn.getpos("'>"))
+
+  local start_row, start_col, end_row, end_col
+
   if csrow < cerow or (csrow == cerow and cscol <= cecol) then
-    return csrow - 1, cscol - 1, cerow - 1, cecol
+    start_row = csrow - 1
+    start_col = cscol - 1
+    end_row = cerow - 1
+    end_col = cecol
   else
-    return cerow - 1, cecol - 1, csrow - 1, cscol
+    start_row = cerow - 1
+    start_col = cecol - 1
+    end_row = csrow - 1
+    end_col = cscol
   end
+
+  -- The last char in ts is equivalent to the EOF in another line.
+  local last_row = vim.fn.line("$")
+  local last_col = vim.fn.col({last_row, "$"})
+  last_row = last_row - 1
+  last_col = last_col - 1
+  if end_row == last_row and end_col == last_col then
+    end_row = end_row + 1
+    end_col = 0
+  end
+
+  return start_row, start_col, end_row, end_col
 end
 
 local function range_matches(node)
@@ -57,8 +78,18 @@ local function select_incremental(get_parent)
     -- Find a node that changes the current selection.
     local node = nodes[#nodes]
     while true do
-      node = get_parent(node)
+      local parent = get_parent(node)
-      if not node then return end
+      if not parent or parent == node then
+        -- Keep searching in the main tree
+        -- TODO: we should search on the parent tree of the current node.
+        local root = parsers.get_parser():parse()[1]:root()
+        parent = root:named_descendant_for_range(csrow, cscol, cerow, cecol)
+        if not parent or parent == node then
+          ts_utils.update_selection(buf, node)
+          return
+        end
+      end
+      node = parent
       local srow, scol, erow, ecol = node:range()
       local same_range = (
         srow == csrow