collections_path vs collections_paths

At the bottom of page 161, the note specifies that since Ansible 2.10 the setting is no longer plural and is named `collections_path`.
However at the beginning of page 162, `I like to explicitly configure collections_paths`.
Since this is revision 2 of the book and it is relevant to Ansible 2.10, the above should also be the new, singular setting `collections_paths`.

Compare the note at the bottom of page 161 with the configuration example at the beginning of page 162. Correct the setting name so both references consistently use the intended singular form, then check the surrounding text for the same inconsistency.

Written by the indexing model from the issue text.