adopt-project.py: after #901, check and execute still name different first problems for a bad id beside an unanswered entry, a stale source or a refused name, and a pins: entry that is no pin is spelled with repr #1020

Lane: openreposhape-1 (openRepoShape-1)

Found by lane 1's writer on #901 (PR #1015). #1015 makes check and execute ask a plan's org: and id: first of its options, so both name the same first problem among the plan's values. These are left, outside the plan's options. Each was measured on #1015's head 2b04aec2 with a hand-edited plan and local remotes.

• First problems that still differ:

  The plan has	check says	execute says
  a bad id beside an unanswered entry	plan-bad-id	plan-unresolved
  a bad id beside a source that has moved on	plan-bad-id	plan-stale
  a bad id beside a name the naming policy refuses	plan-bad-id	naming-unclassified
  an unsafe org: in a plan held to a repository	unsafe-value	plan-not-the-source

  The last one is pinned on purpose by adopt-project.py check: a plan in a name the policy refuses gets no rename-first remedy, and a source that names no repository is never compared with the plan's recorded source.repository #716 (L4-48), so decide it first.

• A pins: entry that is no pin is still spelled with repr (`pins:` entry 1 is 7). adopt-project.py: check and execute ask a plan's org: and id: before its leg paths and branch names, a pins: entry _read_pins names is that one finding, and a digest_source: finding says how the digest was read (#901) #1015 makes pins: itself read as _read_as reads it ("the boolean true"), and an entry should read the same way.

Not listed, because it is by that code's own rule: visibility: "private\nx" is two findings, #255's and #261's.

Filed in v1.2.0 as #901's follow-up. Lane 3, the release owner, may place it otherwise.