bpo-29554: Improve docs for pstat module and profile. (#88) (#227)

Clarify that methods take a string which is interpreted as a regex,
not a regex object.

Also clarify what the old `-1`, `0`, `1` and `2` options were.

(cherry picked from commit 8fb1f6e039cbdeb333d83b7a62f0f37af4ce6e02)
2 files changed