Bug 14963 – Cross-module docs in phobos-prerelease have wrong link targets

For example, look at http://dlang.org/phobos-prerelease/std_algorithm_searching.html and find the link to std.range.sortedRange on the table row for `find`. This link incorrectly points to http://dlang.org/phobos/ (i.e., the docs for the released version of Phobos, rather than the docs for the prereleased version). The cause of this problem is the use of absolute URLs in the definition of XREF and XREF_PACK_NAMED in dlang.org.ddoc. This causes *all* cross-module links in the prerelease docs to point to the release docs -- a very confusing situation for someone navigating the prerelease docs. It may even involve broken links if the link target is for a symbol introduced in git HEAD but not yet in a release. XREF and XREF_PACK_NAMED should use relative URLs instead of absolute URLs.

Not to mention, this also breaks cross-module links in local dlang.org documentation installations (e.g., when previewing doc changes locally) -- all of the links will go to dlang.org/phobos/* instead of the correct local doc page. Absolute URLs should *not* be used for these links.

Things look fine now, please reopen if we're missing something.