toc支持小写占位符

src/extensions/libs/markdownItAnchor.js

@@ -98,7 +98,7 @@ export default (md) => {
           return result;
         }, '');
       }
-      if (token.type === 'inline' && token.content === '[TOC]') {
+      if (token.type === 'inline' && (token.content === '[TOC]' || token.content === '[toc]')) {
         tocTokens.push(token);
       }
     });

src/services/markdownGrammarSvc.js

@@ -107,7 +107,7 @@ export default {
       },
     };
     grammars.main['cn-toc'] = {
-      pattern: /^\[TOC\]$/gm,
+      pattern: /^\[(TOC|toc)\]$/gm,
     };
     for (let i = 6; i >= 1; i -= 1) {
       grammars.main[`h${i} cn-head`] = {