errors/fmt: avoid printing spurious colon

This happened when Detail is called but nothing
is printed.

Also gobble a newline at the start of printing detail.
Gobbling a newline at either the start or end simplifies
implementations, such as printing a list of stack traces.

Change-Id: I01af5c219745104600d01f9b543a054e7c1385f1
Reviewed-on: https://go-review.googlesource.com/c/152998
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
3 files changed
tree: 56d80e94689f7b2b1c77a9c39f64e8b41bc665b6
  1. apidiff/
  2. cmd/
  3. ebnf/
  4. ebnflint/
  5. errors/
  6. fsnotify/
  7. inotify/
  8. io/
  9. mmap/
  10. old/
  11. rand/
  12. shiny/
  13. shootout/
  14. utf8string/
  15. winfsnotify/
  16. .gitattributes
  17. .gitignore
  18. AUTHORS
  19. codereview.cfg
  20. CONTRIBUTING.md
  21. CONTRIBUTORS
  22. LICENSE
  23. PATENTS
  24. README.md
README.md

exp

This subrepository holds experimental and deprecated (in the old directory) packages.

The idea for this subrepository originated as the pkg/exp directory of the main repository, but its presence there made it unavailable to users of the binary downloads of the Go installation. The subrepository has therefore been created to make it possible to go get these packages.

Warning: Packages here are experimental and unreliable. Some may one day be promoted to the main repository or other subrepository, or they may be modified arbitrarily or even disappear altogether.

In short, code in this subrepository is not subject to the Go 1 compatibility promise. (No subrepo is, but the promise is even more likely to be violated by go.exp than the others.)

Caveat emptor.