Many of these functions should be inlineable, but I'm not 100% sure
that they can be inlined without these annotations. We don't want to
force things, but we do try and nudge the compiler in the right
direction.
The top-level listing was just getting a bit too long for my taste. So
put all of the code in one directory and shrink the large top-level mess
to a small top-level mess.
NOTE: This commit only contains renames. The subsequent commit will
actually make ripgrep build again. We do it this way with the naive hope
that this will make it easier for git history to track the renames.
Sigh.
