adds YAML to list of automatically highlighted languages for code blocks (#960)

Resolves: rdar://157242405

Author: heckj

src/setup-utils/vue-config-utils.js

@@ -63,7 +63,7 @@ function baseChainWebpack(config) {
     }]);
 
   // Limit highlight.js to only the necessary languages
-  const builtinLanguages = 'bash|c|s?css|cpp|diff|http|java|llvm|perl|php|python|ruby|xml|javascript|json|markdown|objectivec|shell|swift';
+  const builtinLanguages = 'bash|c|s?css|cpp|diff|http|java|llvm|perl|php|python|ruby|xml|javascript|json|markdown|objectivec|shell|swift|yaml';
   const envLanguages = (process.env.VUE_APP_HLJS_LANGUAGES ?? '').split(',').join('|');
   config
     .plugin('LanguagesPlugin')

src/utils/syntax-highlight.js

@@ -37,6 +37,7 @@ const Languages = {
   shell: ['console', 'shellsession'],
   swift: [],
   xml: ['html', 'xhtml', 'rss', 'atom', 'xjb', 'xsd', 'xsl', 'plist', 'wsf', 'svg'],
+  yaml: ['yml', 'yaml'],
   // load more languages from the environment
   ...(
     process.env.VUE_APP_HLJS_LANGUAGES