I am a beginner in neovim and Lua, but I believe I found a mistake in the documentation.
In the configuration instructions, it is written:
require('telescope').setup {
local project_actions = require 'telescope._extensions.project.actions'
...
This raised a Lua Syntax error. I believe it should be instead
local project_actions = require 'telescope._extensions.project.actions'
require('telescope').setup {
...
Now the variable definition is not done inside the table and the error is not raised.