Revert "Regenerate Core docs 1.8"

This reverts commit b715469c64f8f8b7af91350b54288d0d0c4ac64c.
Fix Ruby 1.8 Core docs

For some strange reason YARD didn't allow me to parse "file.c". It is
giving me the following error:

  [warn]: The proxy IO has not yet been recognized.
  [warn]: If this class/method is part of your source tree, this will
          affect your documentation results.
  [warn]: You can correct this issue by loading the source file for this
          object before `file.c'

I have no idea how to fix that, so the solution is simple: regenerate
everything but "file.c".