sync: improve error messages for invalid update options

[ee7]

Changes:

• Add tests for the fix in d5f5485.

• Try to improve error wordings, and try to reorder list items by likelihood of what the user wanted.

Follow-up from #674 (comment)

---

Before this commit

$ configlet sync -o -uy --tests
Error: '-y, --yes' was provided to non-interactively update, but the tests updating mode is still 'choose'.
You can either:
- remove '-y, --yes', and update by confirming prompts
- or narrow the syncing scope via some combination of --docs, --filepaths, and --metadata
- or add '--tests include' or '--tests exclude' to non-interactively include/exclude missing tests
If no syncing scope option is provided, configlet uses the full syncing scope.
If no --tests value is provided, configlet uses the 'choose' mode.

configlet 4.0.0-beta.6
The official tool for managing Exercism language track repositories.

Usage:
  configlet [global-options] <command> [command-options]
[...]

$ configlet sync -o -u --docs < /dev/null
Error: Configlet was used in a non-interactive context, and the --update option was passed without the --yes option
You can either:
- keep using configlet non-interactively, and remove the --update option so that no destructive changes are performed
- keep using configlet non-interactively, and add the --yes option to perform destructive changes
- use configlet in an interactive terminal

configlet 4.0.0-beta.6
The official tool for managing Exercism language track repositories.

Usage:
  configlet [global-options] <command> [command-options]
[...]

With this commit

$ configlet sync -o -uy --tests
Error: '-y, --yes' was provided to non-interactively update, but tests are in
the syncing scope and the tests updating mode is 'choose'.

You can either:
- use '--tests include' or '--tests exclude' to non-interactively include/exclude
  missing tests
- or narrow the syncing scope via some combination of '--docs', '--filepaths', and
  '--metadata' (removing '--tests' if it was passed)
- or remove '-y, --yes', and update by answering prompts

If no syncing scope option is provided, configlet uses the full syncing scope.
If '--tests' is provided without an argument, configlet uses the 'choose' mode.

----------------------

configlet 4.0.0-beta.6
The official tool for managing Exercism language track repositories.

Usage:
  configlet [global-options] <command> [command-options]
[...]

$ configlet sync -o -u --docs < /dev/null
Error: configlet ran in a non-interactive context, but interaction was required because
'--update' was passed without '--yes', and at least one of docs, filepaths, and
metadata were in the syncing scope.

You can either:
- keep using configlet non-interactively, and add the '--yes' option to perform
  changes without confirmation
- or keep using configlet non-interactively, and remove the '--update' option so
  that configlet performs no changes
- or run the same command in an interactive terminal, to update by answering
  prompts

----------------------

configlet 4.0.0-beta.6
The official tool for managing Exercism language track repositories.

Usage:
  configlet [global-options] <command> [command-options]
[...]