Copilot Skills: Release note generation skill should also quote co-authors (#45819)

<!-- Enter a brief description/summary of your PR here. What does it
fix/what does it change/how was it tested (even manually, if necessary)?
-->
## Summary of the Pull Request

Release note generation skill add support for quoting co-authors

<!-- Please review the items on the PR checklist before submitting-->
## PR Checklist

- [ ] Closes: #xxx
<!-- - [ ] Closes: #yyy (add separate lines for additional resolved
issues) -->
- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [ ] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end-user-facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
- [ ] [YML for CI
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
- [ ] [YML for signed
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/release.yml)
- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

<!-- Provide a more detailed description of the PR, other things fixed,
or any additional comments/features here -->
## Detailed Description of the Pull Request / Additional comments

<!-- Describe how you validated the behavior. Add automated tests
wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed

Result may vary because of uncertainty of LLM, while I can get this
result during my tests

<img width="696" height="147" alt="image"
src="https://github.com/user-attachments/assets/9d20670f-b9fb-4630-b6b4-f94c2a5d2284"
/>

.github/skills/release-note-generation/references/step4-summarization.md

@@ -16,7 +16,7 @@ For each CSV in `Generated Files/ReleaseNotes/grouped_csv/`, create a markdown f
 - Use the “Verb-ed + Scenario + Impact” sentence structure—make readers think, “That’s exactly what I need” or “Yes, that’s an awesome fix.”; The "impact" can be end-user focused (written to convey user excitement) or technical (performance/stability) when user-facing impact is minimal.
 - If nothing special on impact or unclear impact, mark as needing human summary
 - Source from Title, Body, and CopilotSummary (prefer CopilotSummary when available)
-- If the column `NeedThanks` in CSV is `True`, append: `Thanks [@Author](https://github.com/Author)!`
+- The `NeedThanks` column contains a comma-separated list of external contributor usernames who should be thanked (empty = no thanks needed, all authors are core team). For each non-empty `NeedThanks` value, append thanks for **every** listed contributor: `Thanks [@user1](https://github.com/user1)!` for a single contributor, or `Thanks [@user1](https://github.com/user1) and [@user2](https://github.com/user2)!` for two, or `Thanks [@user1](https://github.com/user1), [@user2](https://github.com/user2), and [@user3](https://github.com/user3)!` for three or more.
 - Do NOT include PR numbers in bullet lines
 - Do NOT mention “security” or “privacy” issues, since these are not known and could be leveraged by attackers in earlier versions. Instead, describe the user-facing scenario, usage, or impact.
 - If confidence < 70%, write: `Human Summary Needed: <PR full link>`
@@ -72,13 +72,13 @@ Some items in the Development section may overlap and should be moved to the Mod
 
 ## Advanced Paste
 
-- Wrapped paste option lists in a single ScrollViewer
-- Added image input handling for AI-powered transformations
+- Wrapped paste option lists in a single ScrollViewer in [#5678](https://github.com/microsoft/PowerToys/pull/5678)
+- Added image input handling for AI-powered transformations in [#5679](https://github.com/microsoft/PowerToys/pull/5679)
 ...
 
 ## Awake
 
-- Fixed timed mode expiration. Thanks [@daverayment](https://github.com/daverayment)!
+- Fixed timed mode expiration in [#5680](https://github.com/microsoft/PowerToys/pull/5680) by [@daverayment](https://github.com/daverayment)
 ...
 
 ---