[Tree] Fix getting root nodes for materializedd path if 'path_starts_with_separator'
  or 'path_ends_with_separator' are changed against default
Typo fixes

- remove extra word
- add missing letter
- remove extra letter
Make sure the user knows that both annotations are required

I assume that every field would be tracked if I used the Loggable annotation only.
Merge pull request #811 from laurentChin/loggable_documentation_improvements

Loggable documentation improvements
Merge pull request #810 from Mordred/mp_separators

[Tree] Fix getting root nodes for materialized path