build(docs-infra): never show linenums for triple-backticked code blocks (#31493)

PR Close #31493

aio/tools/transforms/remark-package/services/handlers/code.js

@@ -4,7 +4,9 @@
 module.exports = function code(h, node) {
   var value = node.value ? ('\n' + node.value + '\n') : '';
   var lang = node.lang && node.lang.match(/^[^ \t]+(?=[ \t]|$)/);
-  var props = {};
+  var props = {
+    linenums: 'false'
+  };
 
   if (lang) {
     props.language = lang;

aio/tools/transforms/remark-package/services/renderMarkdown.spec.js

@@ -88,7 +88,7 @@ describe('remark: renderMarkdown service', () => {
     '```';
     const output = renderMarkdown(content);
     expect(output).toEqual(
-    '<code-example language="ts">\n' +
+    '<code-example linenums="false" language="ts">\n' +
     '  class MyClass {\n' +
     '    method1() { ... }\n' +
     '  }\n' +