bug#55905: warn about misplaced or duplicated doc strings, `declare` or `interactive` forms

[Mattias Engdegård]

11 juni 2022 kl. 14.44 skrev Lars Ingebrigtsen <larsi@gnus.org>:

> This is most welcome -- I can never remember myself what the order of
> declare and interactive is.

Same here (which prompted the patch). A slightly updated version has now been 
pushed to master.

There's the possibility of making the parsing more tolerant with respect to 
ordering, and possibly allow multiple `declare` forms. It would be easy enough.