refactor: use stylus iteration to generate the lang tip

Author: ulivz

lib/default-theme/styles/code.styl

@@ -92,40 +92,28 @@ div[class*="language-"]
       border-right 1px solid rgba(0, 0, 0, 66%)
       background-color $codeBgColor
 
-div[class*="language-js"], div[class*="language-javascript"]
+
+for lang in js ts html md vue css sass scss less stylus go java c sh yaml
+  div{'[class*="language-' + lang + '"]'}
+    &:before
+      content ('' + lang)
+
+div[class*="language-javascript"]
   &:before
     content "js"
 
-div[class*="language-ts"], div[class*="language-typescript"]
+div[class*="language-typescript"]
   &:before
     content "ts"
 
-div[class*="language-html"], div[class*="language-markup"]
+div[class*="language-markup"]
   &:before
     content "html"
 
-div[class*="language-markdown"], div[class*="language-md"]
+div[class*="language-markdown"]
   &:before
     content "md"
 
-div[class*="language-vue"]:before
-  content "vue"
-
-div[class*="language-css"]:before
-  content "css"
-
-div[class*="language-sass"]:before
-  content "sass"
-
-div[class*="language-less"]:before
-  content "less"
-
-div[class*="language-scss"]:before
-  content "scss"
-
-div[class*="language-stylus"]:before
-  content "stylus"
-
 div[class*="language-json"]:before
   content "json"
 
@@ -135,17 +123,5 @@ div[class*="language-ruby"]:before
 div[class*="language-python"]:before
   content "py"
 
-div[class*="language-go"]:before
-  content "go"
-
-div[class*="language-java"]:before
-  content "java"
-
-div[class*="language-c"]:before
-  content "c"
-
 div[class*="language-bash"]:before
   content "sh"
-
-div[class*="language-yaml"]:before
-  content "yaml"