Improve English language parsing of known complex policy expression patterns.

[mchernicoff]

We should improve the parsing of English language policy expressions that are complex but follow a known pattern.

For example, the policy expression

(lte (count (filter (eq #t) $)) 0)

for a failed affiliation plugin currently parses to

"Expected the number of elements in "equal to true" filtered on the repository's contributors flagged as affiliated to be less than or equal to 0"

but could say something like

"Expected the number of the repository's contributors flagged as affiliated to be less than or equal to 0"

And the policy expression

(lte (divz (count (filter (eq #f) $)) (count $)) 0.05)

for a failed review plugin currently parses to

"Expected the number of elements in "equal to false" filtered on commits to the repo indicating review or not divided by the number of elements in commits to the repo indicating review or not to be less than or equal to 0.05"

but could say something like

"Expected the percent of commits to the repo not indicating review to be less than or equal to 0.05"

These are suggestions, and even something in between the current and suggested expressions could work.

[mchernicoff]

We could also improve the display of Span duration primitives. Currently they display as an internal jiff format e.g.

"Expected span of time that has elapsed since last activity in repo to be less than or equal to P364D but it was PT44315963.530639277S"

[BurntSushi]

FWIW, that format is ISO 8601. Jiff does also support a "friendly" format for durations.

[mchernicoff]

FWIW, that format is ISO 8601. Jiff does also support a "friendly" format for durations.

Thanks for the tip. I used it in MR #878 to resolve this component of the issue.
It was very simple and easy to use.