Fix projr_dir_ignore not unignoring no-longer-ignored files

[MiguelRodo]

After running projr_dir_ignore with this directories key:

directories:
  data-raw-public:
    path: _data_raw/public
  data-raw-private:
    path: _data_raw/private
  cache:
    path: _tmp
  output:
    path: _output
  docs:
    path: _site

we still had this in .gitignore:

# Start of projr section: do not edit by hand (until `# End of projr section`)
_data_raw/**
_tmp/**
_output/**
_archive/**
_site/**
_data_raw/public/**
_data_raw/private/**
# End of projr section

_data_raw was previously a data-raw path.