Add type annotation for return type of parseQueriesFromInput

Author: mbg

src/config/db-config.ts

@@ -357,7 +357,7 @@ function parseQueriesFromInput(
   rawQueriesInput: string | undefined,
   queriesInputCombines: boolean,
   errorToThrow?: ConfigurationError,
-) {
+): QuerySpec[] | undefined {
   if (!rawQueriesInput) {
     return undefined;
   }