Accessibility add alt to img (#1334)

Signed-off-by: Arhell <[email protected]>

docusaurus.config.js

@@ -159,7 +159,7 @@ module.exports = {
         <br />
         © ${new Date().getFullYear()} The Linux Foundation. All rights reserved. The Linux Foundation has registered trademarks and uses trademarks. For a list of trademarks of The Linux Foundation, please see our <a href="https://www.linuxfoundation.org/trademark-usage/"> Trademark Usage</a> page.
         <br />
-        <a href="https://zzlz.gsxt.gov.cn/businessCheck/verifKey.do?showType=p&serial=913301105865146816-SAIC_SHOW_1000009133011058651468161661997004982&signData=MEYCIQDV2SEwsPqwXWkyqyF/+schpsqmPrjT8uEplDrD7xfdhgIhAKoSoKR6iR+YPF4q4CCLYvm8ruB1nFKRkibUx1A5n/Kn" target="_blank"><img style="width: 20px;margin-bottom: -5px;" src="/img/beian/license.gif"/></a> <a target="_blank" href="http://www.beian.gov.cn/portal/registerSystemInfo?recordcode=33011002016698" style="display:inline-block;text-decoration:none;height:20px;line-height:20px;"><img src="" style="float:left;"/><p style="height:20px;line-height:20px;margin: 0px 0px 0px 5px; color:#939393;">浙公网安备 33011002016698号</p></a> <a href="https://beian.miit.gov.cn/" target="_blank">浙ICP备12022327号-975</a>
+        <a href="https://zzlz.gsxt.gov.cn/businessCheck/verifKey.do?showType=p&serial=913301105865146816-SAIC_SHOW_1000009133011058651468161661997004982&signData=MEYCIQDV2SEwsPqwXWkyqyF/+schpsqmPrjT8uEplDrD7xfdhgIhAKoSoKR6iR+YPF4q4CCLYvm8ruB1nFKRkibUx1A5n/Kn" target="_blank"><img alt="license" style="width: 20px;margin-bottom: -5px;" src="/img/beian/license.gif"/></a> <a target="_blank" href="http://www.beian.gov.cn/portal/registerSystemInfo?recordcode=33011002016698" style="display:inline-block;text-decoration:none;height:20px;line-height:20px;"><img src="" style="float:left;"/><p style="height:20px;line-height:20px;margin: 0px 0px 0px 5px; color:#939393;">浙公网安备 33011002016698号</p></a> <a href="https://beian.miit.gov.cn/" target="_blank">浙ICP备12022327号-975</a>
       `,
     },
     prism: {