chore(lint): remove obsolete spec exceptions

Author: caugner

lint/linter/test-spec-urls.js

@@ -18,16 +18,10 @@ const specsExceptions = [
   // Remove once https://github.com/whatwg/html/pull/6715 is resolved
   'https://wicg.github.io/controls-list/',
 
-  // Exception for April Fools' joke for "418 I'm a teapot"
-  'https://www.rfc-editor.org/rfc/rfc2324',
-
   // Unfortunately this doesn't produce a rendered spec, so it isn't in browser-specs
   // Remove if it is in the main ECMA spec
   'https://github.com/tc39/proposal-regexp-legacy-features/',
 
-  // Remove once tc39/ecma262#3221 is merged
-  'https://github.com/tc39/proposal-regexp-modifiers',
-
   // See https://github.com/w3c/browser-specs/issues/305
   // Features with this URL need to be checked after some time
   // if they have been integrated into a real spec