Feature request: merge docstrings

[wadetregaskis-linkedin]

It'd be great if there were a way for overridden methods to amend the parent docstring in some way - even if just through some kind of dumb string concatenation. Sometimes the overriding method has more useful information to add - e.g. subclass-specific details or behaviours - but having to copy-paste the entire parent docstring creates a maintenance burden, since now the docstrings must be carefully, manually kept synchronised.

Even better would be if common docstring formats were understood, and the merge done more intelligently than just a string concatenation - e.g. param / return values in the override get individually appended to the corresponding lines from the parent.

The exact behavour desired - re. append vs merge vs replace - could be controlled via an optional argument to @overrides.