LSIF: errors thrown on unrecognized request types

Created by: chrismwendt

Some LSIF indexers (e.g. https://github.com/microsoft/lsif-java) emit requests that lsif-server currently doesn't recognize (e.g. textDocument/typeDefinition).

This fixes uploads that include unrecognized requests:

diff --git a/lsif/src/correlator.ts b/lsif/src/correlator.ts
index 3ec1da4a41..00fb3f37de 100644
--- a/lsif/src/correlator.ts
+++ b/lsif/src/correlator.ts
@@ -306,7 +306,7 @@ export class Correlator {
             return
         }
 
-        throw new Error(`Unknown definition or reference result ${edge.outV}.`)
+        console.warn(`Unknown definition or reference result ${edge.outV}.`)
     }
 
     /**