I am inclined to think the article is just wrong, since I can't see any use for any of these items: given the weak number system, it is unlikely we need a decimal point or any ratio marker and poetry lines pretty much take care of themselves (and would be ruined by a spoken or written mark). Nor do we use pounds, shillings and pence, the other major use of the virgule.
Notice that the comma sets of non-restrictive relative clauses and you want to use it for restrictive ones. Non-restrictive clauses present no problems since they are separate information and thus go naturally into separate sentences (problems of referential alignment aside).
I assume that what you want to add after 'pu' is a verb phrase, potentially a verb (with modifiers and complements as needed) + DO (when appropriate) + prepositional phrase (ditto). In short, another whole sentence less the subject (and 'li' which might yet turn up in conjoined predicates), which is supplied by the noun before 'pu'. Assuming 'li' does not occur, this makes few problems for a subject noun, since the 'li' puts and end to that slot. As a DO, there is the problem of whether the next DO is part of the relative clause or another parallel to its head. And a similar problem arises about whether the PP is in the relative clause or in the main clause. This latter arises also with 'pu' clauses in the noun part of PPs. For noun complements, both problems arise again.
That being said, I do think that we need to deal with the situations that restrictive relative clauses are designed to meet, namely narrowing the range of general words for a particular context, where the narrowing cannot be handled easily by adjective style modifiers, The obvious solution, aside from recreating restrictive relative clauses, is to do the restriction first and then take that up: 'waso li tawa noku taso. waso ni li ...'. Perhaps 'waso' needs to be explicitly modified to make clear that on some birds are meant.