Update issue templates

Author: nmetulev

.github/ISSUE_TEMPLATE/documentation.md

@@ -0,0 +1,14 @@
+---
+name: Documentation
+about: 'Documentation suggestion or fix '
+title: "[Docs] "
+labels: 'Area: Documentation'
+assignees: ''
+
+---
+
+<!-- ISSUES MISSING IMPORTANT INFORMATION MAY BE CLOSED WITHOUT INVESTIGATION. -->
+<!-- Please make sure you are posting an issue pertaining to the Microsoft Graph Toolkit. -->
+
+## Description
+<!-- A clear and concise description of what the request is. Add links to existing documentation if any -->