Update old wiki links (#149544)

Part of https://github.com/flutter/flutter/issues/145009

Finishes updating links in the repo that pointed to the old wiki

.github/ISSUE_TEMPLATE/7_cherry_pick.yml

@@ -38,7 +38,7 @@ body:
       label: Changelog Description
       description: >-
         Explain this CP in less than 80 characters that is accessible to most Flutter developers
-        See https://github.com/flutter/flutter/wiki/Hotfix-Documentation-Best-Practices for examples
+        See https://github.com/flutter/flutter/blob/main/docs/releases/Hotfix-Documentation-Best-Practices.md for examples
     validations:
       required: true
   - type: input

.github/ISSUE_TEMPLATE/8_design_doc.yml

@@ -8,7 +8,7 @@ body:
         Thank you for your interest in contributing to Flutter!
 
         Please ensure that you are following
-        https://github.com/flutter/flutter/wiki/Design-Documents
+        https://github.com/flutter/flutter/blob/main/docs/contributing/Design-Documents.md
         when sharing a design document.
 
         Please fill out the sections below to the best of your ability.

.github/PR_TEMPLATE/PULL_REQUEST_CP_TEMPLATE.md

@@ -1,4 +1,4 @@
-This pull request is created by [automatic cherry pick workflow](https://github.com/flutter/flutter/wiki/Flutter-Cherrypick-Process#automatically-creates-a-cherry-pick-request)
+This pull request is created by [automatic cherry pick workflow](https://github.com/flutter/flutter/blob/main/docs/releases/Flutter-Cherrypick-Process.md#automatically-creates-a-cherry-pick-request)
 Please fill in the form below, and a flutter domain expert will evaluate this cherry pick request.
 
 ### Issue Link:
@@ -7,7 +7,7 @@ What is the link to the issue this cherry-pick is addressing?
 < Replace with issue link here >
 
 ### Changelog Description:
-Explain this cherry pick in one line that is accessible to most Flutter developers. See [best practices](https://github.com/flutter/flutter/wiki/Hotfix-Documentation-Best-Practices) for examples
+Explain this cherry pick in one line that is accessible to most Flutter developers. See [best practices](https://github.com/flutter/flutter/blob/main/docs/releases/Hotfix-Documentation-Best-Practices.md) for examples
 
 < Replace with changelog description here >
 

.github/PULL_REQUEST_TEMPLATE.md

@@ -19,13 +19,13 @@
 If you need help, consider asking for advice on the #hackers-new channel on [Discord].
 
 <!-- Links -->
-[Contributor Guide]: https://github.com/flutter/flutter/wiki/Tree-hygiene#overview
-[Tree Hygiene]: https://github.com/flutter/flutter/wiki/Tree-hygiene
-[test-exempt]: https://github.com/flutter/flutter/wiki/Tree-hygiene#tests
-[Flutter Style Guide]: https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo
-[Features we expect every widget to implement]: https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#features-we-expect-every-widget-to-implement
+[Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
+[Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
+[test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
+[Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
+[Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
 [CLA]: https://cla.developers.google.com/
 [flutter/tests]: https://github.com/flutter/tests
-[breaking change policy]: https://github.com/flutter/flutter/wiki/Tree-hygiene#handling-breaking-changes
-[Discord]: https://github.com/flutter/flutter/wiki/Chat
-[Data Driven Fixes]: https://github.com/flutter/flutter/wiki/Data-driven-Fixes
+[breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
+[Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
+[Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

.github/workflows/easy-cp.yml

@@ -81,7 +81,7 @@ jobs:
         if: ${{ failure() && steps.attempt-cp.conclusion == 'failure' }}
         run: |
           FAILURE_MSG="Failed to create CP due to merge conflicts.<br>"
-          FAILURE_MSG+="You will need to create the PR manually. See [the cherrypick wiki](https://github.com/flutter/flutter/wiki/Flutter-Cherrypick-Process) for more info."
+          FAILURE_MSG+="You will need to create the PR manually. See [the cherrypick wiki](https://github.com/flutter/flutter/blob/main/docs/releases/Flutter-Cherrypick-Process.md) for more info."
           gh pr comment ${{ github.event.pull_request.number }} -R flutter/flutter -b "${FAILURE_MSG}"
         env:
           GITHUB_TOKEN: ${{ secrets.FLUTTERACTIONSBOT_CP_TOKEN }}