Include section in telemetry readme about data _not_ being collected

Author: aeisenberg

.github/TELEMETRY.md

@@ -14,6 +14,15 @@ GitHub collects anonymous information related to the usage of the extensions. Th
 - Anonymous GUID to uniquely identify an installation.
 - IP address of the client sending the telemetry data. This IP address is not stored. It is discarded immediately after the telemetry data is received.
 
+## What data is **NOT** collected?
+
+We are careful to only collect the minimal amount of data we need to answer the questions about how our users are experiencing this product. So this means that we do not collect the following information:
+
+- No GitHub user ID
+- No CodeQL database names
+- No queries or anything about them
+- No filesystem paths.
+
 ## How do I disable telemetry reporting?
 
 You can disable telemetry reporting by setting `codeQL.telemetry.enableTelemetry` to `false` in [your settings](https://code.visualstudio.com/docs/getstarted/settings#_settings-editor).