feat: 新增設置代碼行數限制，顯示展開按鈕

improvement: prismjs 可以配置 code_word_wrap
improvement: 搜索 hover 效果與其它目錄一致
improvement: css 優化
fix: 修復prismjs 無法識別的語言 顯示 null 而不是顯示 code 的 bug
fix: 修復默認代碼大小不會隨着字體放大/放小而改變的bug
fix: 修復prismjs 在ios safari 下自動換行的bug

source/css/_highlight/prismjs/index.styl

@@ -7,7 +7,7 @@ if $highlight_theme != false
 #article-container
   pre[class*='language-']
     &::-webkit-scrollbar-thumb
-      background: $highlight-scrollbar
+      background: var(--hlscrollbar-bg)
 
     &:not(.line-numbers)
       padding: 10px 20px

source/css/_highlight/prismjs/line-number.styl

@@ -8,9 +8,16 @@
 
       > code
         position: relative
-        white-space: inherit
         line-height: $line-height-code-block
 
+        if hexo-config('code_word_wrap')
+          white-space: pre-wrap
+        else
+          white-space: inherit
+          word-wrap: normal
+          word-break: normal
+          overflow-wrap: normal
+
       .line-numbers-rows
         position: absolute
         top: 0
@@ -29,6 +36,6 @@
           &:before
             display: block
             padding-right: .8em
-            color: $highlight-gutter.color
+            color: var(--hlnumber-color)
             content: counter(linenumber)
             text-align: right