Document soft assertions: explain -ErrorAction on generated Should-* pages + add a dedicated "Soft assertions" entry #385

Summary

Pester v6's "soft assertion" behaviour (collect all failures instead of stopping at the first one) is under-documented and hard to discover. The word "soft assertion" does not appear anywhere on https://pester.dev today — the feature is only described at the bottom of the Should page under the heading "Collect all Should failures".

This issue tracks two related documentation improvements.

1. Document -ErrorAction on the generated Should-* Command Reference pages

On every generated Should-* page (e.g. Should-Be), -ErrorAction currently only shows up in the generic boilerplate line:

This cmdlet supports the common parameters: -Debug, -ErrorAction, …

There is no hint that, for assertions, -ErrorAction is the knob that controls soft-assertion behaviour:

• -ErrorAction Continue — record the failure but keep going (soft assertion)
• -ErrorAction Stop — fail the test immediately (e.g. to guard a precondition before continuing)

We should surface this per-assertion meaning on the generated pages (e.g. via the comment-based help description/notes for the Should-* commands).

⚠️ Note: the Command Reference pages are auto-generated from comment-based help in the pester/pester source, so the actual text change for this part needs to land there. Filing here to track the overall documentation gap.

2. Add a dedicated "Soft assertions" entry describing how to enable them for every assertion

Add a discoverable entry (own section/page in the Assertions section) that:

• Uses the term "soft assertions" explicitly so it's searchable.

• Explains how to turn them on globally for every assertion, rather than per-assertion:

  $config = New-PesterConfiguration
  $config.Should.ErrorAction = 'Continue'
  # or via $PesterPreference.Should.ErrorAction = 'Continue'

• Notes that the global setting is honoured by both the classic Should -Be syntax and the new Should-* assertions.

• Shows how to override it on a single assertion with -ErrorAction Stop (precondition) / -ErrorAction Continue.

• Cross-links from / consolidates the existing "Collect all Should failures" section.

Suggested section

Assertions

References

• Assertions / Should page: https://pester.dev/docs/assertions/should-command (existing "Collect all Should failures" section)
• Example generated page: https://pester.dev/docs/commands/Should-Be