[sl4f] Dart null safety: convert the rest of sl4f/client/

diagnostics.dart: Fix places where the code is returning a value even
though the return type is 'void'.

inspect.dart: Remove a return statement that's unreachable because the
switch covers all the enum cases.

Bug: 120221
Test: fx set terminal.x64 --release --with sdk/testing/sl4f/client:tests
  + fx test sl4f_client_tests
Change-Id: I1e7ac4277dd11b9a176b2cff210291923d5e7fb3
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/796582
Commit-Queue: Mark Seaborn <mseaborn@google.com>
Reviewed-by: Gwen Mittertreiner <gmtr@google.com>
API-Review: Gary Bressler <geb@google.com>
20 files changed
tree: 2152026f2c247e4cdac2b930ba88f6fdd2018ca0
  1. boards/
  2. build/
  3. bundles/
  4. docs/
  5. examples/
  6. products/
  7. scripts/
  8. sdk/
  9. src/
  10. third_party/
  11. tools/
  12. zircon/
  13. .clang-format
  14. .clang-tidy
  15. .editorconfig
  16. .git-blame-ignore-revs
  17. .gitattributes
  18. .gitignore
  19. .gitmodules
  20. .gn
  21. .style.yapf
  22. analysis_options.yaml
  23. AUTHORS
  24. BUILD.gn
  25. CODE_OF_CONDUCT.md
  26. CONTRIBUTING.md
  27. fuchsia.code-workspace
  28. LICENSE
  29. OWNERS
  30. PATENTS
  31. pyrightconfig.json
  32. README.md
  33. rustfmt.toml
README.md

Fuchsia

What is Fuchsia?

Fuchsia is an open source, general purpose operating system supporting modern 64-bit Intel and ARM processors.

We expect everyone interacting with our project to respect our code of conduct.

Read more about Fuchsia's principles.

How can I build and run Fuchsia?

See Getting Started.

Where can I learn more about Fuchsia?

See fuchsia.dev.