add products taxonomy to improve findability (#87)

dotnet/docfx.json

@@ -58,6 +58,7 @@
       "manager": "wpickett",
       "searchScope": [".NET"],
       "ms.prod": "dotnet-roslyn-api",
+      "products": ["https://authoring-docs-microsoft.poolparty.biz/devrel/7696cda6-0510-47f6-8302-71bb5d2e28cf"],
       "ms.topic": "managed-reference",
       "ms.technology": "microsoft.codeanalysis",
       "uhfHeaderId": "MSDocsHeader-DotNet",