Update taxonomies.md

Spent five minutes confused because the documentation here is out of sync as all of these are now seem to be under the "taxonomies" slug where the documentation implied the singulars were under "taxonomy".
Merge branch 'master' into davidbhayes-patch-1

Conflicts:
	docs/routes/taxonomies.md
Merge pull request #364 from WP-API/davidbhayes-patch-1

Update Taxonomy route docs with correct paths.  Fixes #355.