Add documentation issue template (#1907)

Author: samfreund

Diff for: .github/ISSUE_TEMPLATE/docs_issue.md

@@ -0,0 +1,17 @@
+---
+name: Documentation Request
+about: Something needs to be documented/updated in the documentation
+title: ''
+labels: documentation
+assignees: ''
+
+---
+
+**Are you requesting documentation for a new feature, or updated documentation for an old feature?**
+Put the feature you are requesting documentation for here, along with whether the documentation is stale and needs to be updated, or whether the documentation does not exist, and needs to be created.
+
+**Where is it?**
+Put the location of the documentation that needs to be updated here.  If you're requesting documenation for a new feature, put where you think it should go.
+
+**Additional context**
+Add any other context or screenshots about the feature request here.