fix readme code block

.markdownlint.json

@@ -3,7 +3,6 @@
   "no-inline-html": false,
   "no-duplicate-header": false,
   "no-emphasis-as-header": false,
-  "fenced-code-language": false,
   "line-length": false,
   "frontmatter": false
 }

README-EN.md

@@ -44,7 +44,7 @@ In a nutshell, you are free to share and adapt, but you must give the appropriat
 
 If you would like to cite this GitHub repo, you can use the bibtex below：
 
-```
+```plain
 @misc{mtfwiki,
   author = {MtF Wiki Team},
   title = {MtF Wiki},

README-ES.md

@@ -44,7 +44,7 @@ Usted es libre de compartir y adaptar, Usted debe dar crédito de manera adecuad
 
 Si quieres citar este GitHub repo, puedes usar el bibtex：
 
-```
+```plain
 @misc{mtfwiki,
   author = {MtF Wiki Team},
   title = {MtF Wiki},

README-T.md

@@ -41,7 +41,7 @@ MtF Wiki 致力於成為一個免費開放且持續更新的跨性別知識整
 
 而如果你想要引用這個 GitHub Repo，可以使用如下的 bibtex：
 
-```
+```plain
 @misc{mtfwiki,
   author = {MtF Wiki Team},
   title = {MtF Wiki},

README.md

@@ -41,7 +41,7 @@ MtF Wiki 致力于成为一个免费开放且持续更新的跨性别知识整
 
 而如果你想要引用这个 GitHub 仓库，可以使用如下的 BibTeX：
 
-```
+```plain
 @misc{mtfwiki,
   author = {MtF Wiki Team},
   title = {MtF Wiki},