eslint: Enable lines-around-directive.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

.eslintrc.json

@@ -38,6 +38,7 @@
             }
         ],
         "import/unambiguous": "error",
+        "lines-around-directive": "error",
         "new-cap": "error",
         "no-alert": "error",
         "no-array-constructor": "error",

tools/check-openapi

@@ -1,4 +1,5 @@
 #!/usr/bin/env node
+
 "use strict";
 
 const fs = require("fs");