Correct docs for Dateish.[days-in-month|is-leap-year]
Correct docs for Dateish.[days-in-month|is-leap-year]

The argument-taking candidates of the two methods were never part of
the Perl 6 specification and have now been removed[^1] from Rakudo.

[1] https://github.com/rakudo/rakudo/commit/6aab64103f1c6ce509be79783d2fd10a989b6edd

MasterDuke17/doc,stmuk/doc,antquinonez/doc,dmaestro/doc,gfldex/doc,jonathanstowe/doc,MasterDuke17/doc,perl6/doc,antquinonez/doc,jonathanstowe/doc,dmaestro/doc,jonathanstowe/doc,gfldex/doc,perl6/doc,dmaestro/doc,stmuk/doc,gfldex/doc,gfldex/doc,perl6/doc,gfldex/doc,antquinonez/doc,MasterDuke17/doc,stmuk/doc,tbrowder/doc,MasterDuke17/doc,tbrowder/doc,antquinonez/doc,stmuk/doc,perl6/doc,dmaestro/doc,stmuk/doc,jonathanstowe/doc,tbrowder/doc,dmaestro/doc,perl6/doc,tbrowder/doc,jonathanstowe/doc,antquinonez/doc