[Rd] help(".libPaths"): Paragraph lacks mentioning of R_LIBS_SITE

[Henrik Bengtsson]

In ?base::.libPaths, there's a paragraph saying:

The library search path is initialized at startup from the environment
variable R_LIBS (which should be a colon-separated list of directories
at which R library trees are rooted) followed by those in environment
variable R_LIBS_USER. Only directories which exist at the time will be
included.

Shouldn't R_LIBS_SITE also be mentioned in that passage?  Something like:

...followed by those in environment variables R_LIBS_USER and R_LIBS_SITE. ...

/Henrik