generate informative doc comments from headers
nimterop should allow generating doc comments for each decl generated; and this could be customizable (eg via an enum)

* pretty sure treesitter exposes comments, so might as well use them to generate doc comments, that way we can have half decent (or more) docs for free

* doc comment could also specify the corresponding declaration from source function

* furthermore, w the plugin idea we discussed, a wrapper writer can provide his definition for a symbol inside `onSymbol(..)`, and can be creative about it in a way that'd be impossible for nimterop to handle, for eg:
* using doxygen
* custom weird formats like ncurses; not sure where doc comments are for symbols for ncurses ; maybe https://github.com/mirror/ncurses/blob/master/doc/ncurses-intro.doc ( see also https://invisible-island.net/ncurses/man/curs_printw.3x.html); 

*  @rnowley how did u insert doc comments in https://github.com/rnowley/nim-ncurses/blob/master/ncurses.nim ?
