Update ISSUE_TEMPLATE.md (#474)

* Update ISSUE_TEMPLATE.md

This change updates the issue template to recommend that any issue about PowerShell syntax coloring should be sent to the EditorSyntax repo.

* Fix typo in ISSUE_TEMPLATE.md

Author: daviwil

ISSUE_TEMPLATE.md

@@ -1,4 +1,13 @@
-**Please fill in these details so that we can help you!**
+<!--
+
+Please fill in these details so that we can help you!
+
+If you are filing an issue related to PowerShell syntax coloring/highlighting,
+please file it at the EditorSyntax repo:
+
+https://github.com/PowerShell/EditorSyntax/issues
+
+-->
 
 ### System Details
 
@@ -18,4 +27,4 @@ I am experiencing a problem with...
 ### Attached Logs
 
 Follow the instructions in the [README](https://github.com/PowerShell/vscode-powershell#reporting-problems)
-about capturing and sending logs.
+about capturing and sending logs.