help.lint,tools.deprecation,tools.test: errors that aren't that horrible...

Deprecation warnings are annoying. If you are using some vocab with deprecated words, your prompt will forever say `:deprecations - show N deprecated word usages`. And there is no way to dismiss that warning. 

Root cause is that deprecation errors have `fatal?` set to `t`. But it and some of its friends are benign and not that fatal at all.