fix package-level docs to generate alias without @docType

[mbjones]

Dear maintainer,

You have file 'redland/man/redland.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 redland-package

if remaining with the old approach.

Please fix in your master sources as appropriate, and submit a fixed
version of your package within the next few months.

Best,
-k

[mbjones]

Working on this in branch bug-107-fix-package-docs but I'm running into an error using roxygen2 to generate the docs. Here's the error when I run roxygen2::roxyngenize():

Error in assign(name, fdef, where) : 
  cannot change value of locked binding for 'delete'

View stacktrace

11. assign(name, fdef, where)
10. .GenericAssign(name, fdef, where)
9. setGeneric("delete", function(obj) standardGeneric("delete")) at redland.R#62
8. eval(ei, envir)
7. eval(ei, envir)
6. withVisible(eval(ei, envir))
5. source(file = filePath, local = as.environment(tmpEnv)) at mergeNamespace_roclet.R#64
4. roclet_process.roclet_mergeNamespace(X[[i]], ...)
3. FUN(X[[i]], ...)
2. lapply(roclets, roclet_process, blocks = blocks, env = env, base_path = base_path)
1. roxygen2::roxygenize()

The error seems to be complaining about the definition of the generic function for delete in https://github.com/ropensci/redland-bindings/blob/bug-107-fix-package-docs/R/redland/R/redland.R#L62 but I am not clear on why this is cropping up now but not historically.

[mbjones]

@jeroen @cboettig or other R gurus -- any pointers on this roxygen issue for redland? Seems like a pretty generic (ha!) problem. I should have submitted this with the last release but I needed to get it done today to avoid getting archived.