[fairbearlab]

Description

The cloudevents/spec repository renamed its default branch from master to
main and moved spec.md to cloudevents/spec.md, so
https://github.com/cloudevents/spec/blob/master/spec.md now returns 404.

This updates three code comments in src/CloudEventsPowerShell/CloudEvents.Sdk.psm1
that point at the datacontenttype attribute to the file's current location:

https://github.com/cloudevents/spec/blob/main/cloudevents/spec.md#datacontenttype

Only the URL text changes (3 lines). These are plain # comments inside
function bodies, not comment-based help, so they are not shown by Get-Help;
only people reading the source see them.

Related to #56, which fixes the README community links for the same root cause
(the cloudevents/spec restructure). This PR does not touch the README.

Left unchanged on purpose:

• Links pinned to v1.0.1 (spec.md, http-protocol-binding.md). They still
  return 200 and their anchors still exist.
• CHANGELOG.md contains no cloudevents/spec links, so there is no history
  to leave as-is.

Type of change

Please mark options that are relevant:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to
  not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Comment-only change; no code behaviour is affected.

• Checked every github.com/cloudevents/spec URL in the repo with
  curl -L: the old master/spec.md URL returns 404, the new
  main/cloudevents/spec.md URL returns 200, and the v1.0.1 links return 200.
• Checked the anchor against the headings of cloudevents/spec.md on
  main: there is exactly one #### datacontenttype heading (the attribute
  definition), so #datacontenttype resolves to the intended section.
• git diff --check is clean; line endings (LF) and encoding are unchanged.

Test Configuration:

• Toolchain: n/a (comment-only change)
• SDK: n/a

Checklist:

• My code follows the contribution
  guidelines
  of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[embano1]

Thx