Need chromer-package alias

[kbroman]

Problem reported by CRAN:

You have file 'chromer/man/chromer.Rd' with \docType{package}, likely intended as a package overview help file, but without the appropriate PKGNAME-package \alias as per "Documenting packages" in R-exts.

This seems to be the consequence of the breaking change

Using @doctype package no longer automatically adds a -package alias. Instead document _PACKAGE to get all the defaults for package documentation.

in roxygen2 7.0.0 (2019-11-12) having gone unnoticed, see r-lib/roxygen2#1491.

As explained in the issue, to get the desired PKGNAME-package \alias back, you should either change to the new approach and document the new special sentinel

 "_PACKAGE"

or manually add

@aliases chromer-package

if remaining with the old approach.