Tweak warning language in templates (#15920)

Author: janiceilene

.github/ISSUE_TEMPLATE/config.yml

@@ -1,8 +1,5 @@
 blank_issues_enabled: false
 contact_links:
-  - name: Start a discussion
-    url: https://github.com/github/docs/discussions/new
-    about: Use a discussion to suggest a new idea or share what you've learned in our docs.
   - name: GitHub Support
     url: https://support.github.com/contact
     about: Contact Support if you're having trouble with your GitHub account.

.github/ISSUE_TEMPLATE/improve-existing-docs.md

@@ -7,7 +7,7 @@ labels:
 assignees: ''
 ---
 <!--
-HUBBERS BEWARE! THIS REPO IS PUBLIC TO THE ENTIRE INTERNET. OPEN AN ISSUE IN GITHUB/DOCS-CONTENT https://github.com/github/docs-content/issues/new/choose INSTEAD.
+HUBBERS BEWARE! THE GITHUB/DOCS REPO IS PUBLIC TO THE ENTIRE INTERNET. OPEN AN ISSUE IN GITHUB/DOCS-CONTENT https://github.com/github/docs-content/issues/new/choose INSTEAD.
 -->
 
 <!--

.github/ISSUE_TEMPLATE/improve-the-site.md

@@ -7,7 +7,7 @@ assignees: ''
 ---
 
 <!--
-HUBBERS BEWARE! THIS REPO IS PUBLIC TO THE ENTIRE INTERNET. OPEN AN ISSUE IN GITHUB/DOCS-CONTENT https://github.com/github/docs-content/issues/new/choose INSTEAD.
+HUBBERS BEWARE! THE GITHUB/DOCS REPO IS PUBLIC TO THE ENTIRE INTERNET. OPEN AN ISSUE IN GITHUB/DOCS-CONTENT https://github.com/github/docs-content/issues/new/choose INSTEAD.
 -->
 
 <!--

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,5 +1,5 @@
 <!--
-HUBBERS BEWARE! THIS REPO IS PUBLIC TO THE ENTIRE INTERNET. OPEN AN ISSUE IN GITHUB/DOCS-CONTENT https://github.com/github/docs-content/issues/new/choose INSTEAD.
+HUBBERS BEWARE! THE GITHUB/DOCS REPO IS PUBLIC TO THE ENTIRE INTERNET. OPEN AN ISSUE IN GITHUB/DOCS-CONTENT https://github.com/github/docs-content/issues/new/choose INSTEAD.
 -->
 
 <!--