largefiles: improve comments, internal docstrings - fix some ungrammatical/unclear/incorrect comments/docstrings - rewrite some really unclear comments/docstrings - make formatting/style more consistent with the rest of Mercurial (lowercase without period unless it's really multiple sentences) - wrap to 75 columns - always say "largefile(s)", not "lfile(s)" (or "big files") - one space between sentences, not two