语法高亮，滚动条美化，设置页面调整

docs/linux/dnsdomainname.html

@@ -3,11 +3,11 @@
 <h2 id="补充说明">补充说明</h2>
 <p><strong>dnsdomainname命令</strong> 用于定义DNS系统中FQDN名称中的域名。</p>
 <h3 id="语法">语法</h3>
-<pre><code>dnsdomainname(选项)</code></pre>
+<pre><code class="language-bash">dnsdomainname(选项)</code></pre>
 <h3 id="选项">选项</h3>
 <p>-v：详细信息模式，输出指令执行的详细信息。</p>
 <h3 id="实例">实例</h3>
-<pre><code>[root@AY1307311912260196fcZ ~]# dnsdomainname -v
+<pre><code class="language-bash">[root@AY1307311912260196fcZ ~]# dnsdomainname -v
 gethostname()=`AY1307311912260196fcZ&#39;
 Resolving `AY1307311912260196fcZ&#39; ...
 Result: h_name=`AY1307311912260196fcZ&#39;