Generate declaration file from tests

ahejlsberg · ahejlsberg · commit 7e0766988543 · 2019-06-06T09:41:44.000-07:00
diff --git a/tests/cases/compiler/numericEnumMappedType.ts b/tests/cases/compiler/numericEnumMappedType.ts
@@ -1,4 +1,5 @@
 // @strict: true
+// @declaration: true
 
 // Repro from #31771
 
