Fix 5ff7b83fdd74bc9f5aaeca6d2289dfdb87ab5994.
Anonymous: fix help for allowPrivateTarget

This fixes some grammar issues previously discussed at #limnoria.
Merge pull request #868 from GLolol/patch-1

Anonymous: fix help for allowPrivateTarget
RSS: Prevent errors if users do not use @announce add correctly. Closes GH-869.