Add template for documentation issues

.github/ISSUE_TEMPLATE/documentation.md

@@ -0,0 +1,32 @@
+---
+name: Documentation
+about: Report an issue with our documentation
+labels: 'type: documentation, triage'
+assignees: ''
+
+---
+
+<!--
+  - Thanks for helping us improve our developer site documentation!
+  - Use this template to describe issues with the content at
+  - developers.google.com/blockly/guides
+  -->
+
+**Where**
+
+<!-- A link to the page with the documentation you want us to update.
+  -  More specific is better.  If no page exists, describe what the page
+  -  should be, and where.
+  -->
+
+**Old content**
+
+<!-- What the documentation currently says -->
+
+**Suggested content**
+
+<!-- Your suggestion for improved documentation -->
+
+**Additional context**
+
+<!-- Add any other context about the problem here. -->