Add subscript to issue templates (#14359)

Co-authored-by: otelbot <197425009+otelbot@users.noreply.github.com>

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -48,3 +48,10 @@ body:
     attributes:
       label: Additional context
       description: Add any other context about the problem here.
+  - type: dropdown
+    attributes:
+      label: Tip
+      description: This element is static, used to render a helpful sub-heading for end-users and community members to help prioritize issues. Please leave as is.
+      options:
+        - <sub>[React](https://github.blog/news-insights/product-news/add-reactions-to-pull-requests-issues-and-comments/) with 👍 to help prioritize this issue. Please use comments to provide useful context, avoiding `+1` or `me too`, to help us triage it. Learn more [here](https://opentelemetry.io/community/end-user/issue-participation/).</sub>
+      default: 0

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -22,3 +22,10 @@ body:
     attributes:
       label: Additional context
       description: Add any other context or screenshots about the feature request here.
+  - type: dropdown
+    attributes:
+      label: Tip
+      description: This element is static, used to render a helpful sub-heading for end-users and community members to help prioritize issues. Please leave as is.
+      options:
+        - <sub>[React](https://github.blog/news-insights/product-news/add-reactions-to-pull-requests-issues-and-comments/) with 👍 to help prioritize this issue. Please use comments to provide useful context, avoiding `+1` or `me too`, to help us triage it. Learn more [here](https://opentelemetry.io/community/end-user/issue-participation/).</sub>
+      default: 0