Output location of `fn` that matched the `Step`

[ilslv]

Synopsis

Often I find myself struggling to find fn, that matched the Step, especially to debug the failure.

Solution

Output step::Location of the fn that matched Step:

• For every test case in writer::Libtest, in case --show-output option is enabled. Only for failed ones otherwise.
• Only failed ones inside writer::Basic, writer::Json and writer::Junit

Checklist

• Created PR:
  • [x] In draft mode
  • [x] Name contains Draft: prefix
  • [x] Name contains issue reference
  • [x] Has assignee
• [x] Documentation is updated (if required)
• [x] Tests are updated (if required)
• [x] Changes conform code style
• [x] CHANGELOG entry is added (if required)
• [x] FCM (final commit message) is posted
  • [x] and approved
• [x] Review is completed and changes are approved
• Before merge:
  • [x] Milestone is set
  • [x] PR's name and description are correct and up-to-date
  • [x] Draft: prefix is removed
  • [x] All temporary labels are removed

[ilslv]

FCM

Output location of `fn` matching a `Step` (#221)

Additionally:
- strip `CARGO_MANIFEST_DIR` from output paths whenever is possible