Ignore methods and functions by decorator

[bentheiii]

We'd like the option to ignore functions marked with certain decorators. This is mostly useful for services and frameworks, where certain decorators can mark a function as a route or option, and the docstring has special meanings.

[terrencepreilly]

That seems reasonable. There's a similar flag, --ignore-regex, which allows you to ignore functions which match a given regex. Perhaps something similar could be added for decorators? (Like, --decorator-ignore-regex, or something.) Feel free to open a PR.