Adds support documentation link

.github/ISSUE_TEMPLATE/config.yml

@@ -3,6 +3,9 @@ contact_links:
     - name: Q & A
       url: https://github.com/gitkraken/vscode-gitlens/discussions?discussions_q=category%3AQ%26A
       about: Ask and answer questions about GitLens
+    - name: Documentation
+      url: https://help.gitkraken.com/gitlens
+      about: Read the GitLens support documentation
     - name: GitLens+ Support
       url: https://www.gitkraken.com/gitlens-support
       about: Get email support for GitLens+ issues and questions