fix(treesitter): do not link @error by default

The @error capture is used for tree-sitter's ERROR node, which indicates
a parsing error -- which can be quite frequent (and jarring) while typing.

Users can still manually `hi link @error Error` in their config.

test/functional/treesitter/highlight_spec.lua

@@ -106,6 +106,7 @@ describe('treesitter highlighting', function()
     }
 
     exec_lua([[ hl_query = ... ]], hl_query)
+    command [[ hi link @error ErrorMsg ]]
     command [[ hi link @warning WarningMsg ]]
   end)