GitLab

No semantics change; this is a "sed refactor" in complexity.

Literally:

- `s/TraversalReason/VisitReason/g`
- `s/TraversalProgress/Progress/g`
- `s/TraversalConfig/Config/g`
- `s/Traverse(/WalkMatching(/g`
- `s/TraverseInformatively(/WalkAdv(/g`
- `s/TraverseTransform/WalkTransforming/g`

There's a few more internally, but the above covers all of the public
exported interface changes.

These changes generally reduce stutter
(e.g. previously traversal.TraversalProgress was quite a gulp),
and mostly result in shorter function names and signatures overall
(and the signatures are particularly noticable, since VisitFuncs are
often actually declared inline by calling code).

A few docs strings also received manual touch-up.
Signed-off-by: Eric Myhre <hash@exultant.us>