feat(code): optimize code block style

assets/css/_partial/_single/_code.scss

@@ -38,7 +38,7 @@ code, pre {
 }
 
 .code-block {
-  line-height: 1.4em;
+  line-height: 1.25rem;
   margin: .5rem 0;
 
   .code-header {

layouts/partials/plugin/code-block.html

@@ -13,7 +13,7 @@
 {{- $result := transform.Highlight $content $lang $options -}}
 <div class="code-block{{ if $lineNos }} code-line-numbers{{ end }}{{ if le $lines $maxShownLines }} open{{ end }}" style="counter-reset: code-block {{ sub $lineNoStart 1 }}">
     <div class="code-header language-{{ $lang }}">
-        <span class="code-title"><i class="arrow fas fa-chevron-right fa-fw" aria-hidden="true"></i></span>
+        <span class="code-title"><i class="arrow fas fa-angle-right fa-fw" aria-hidden="true"></i></span>
         <span class="ellipses"><i class="fas fa-ellipsis-h fa-fw" aria-hidden="true"></i></span>
         {{ if $copy }}<span class="copy" title="{{ T "copyToClipboard" }}"><i class="far fa-copy fa-fw" aria-hidden="true"></i></span>{{ end }}
     </div>