translation for blog on navbar and remove target="_blank" for internal links (#44)

- Do not use `target="_blank"`for gitea websites on navbar (same behavior as about.gitea.com)

- Translate "blog" on navbar for zh-cn

Before:

![Screen Shot 2023-07-12 at 17.40.27](/attachments/8c2d2a0d-5b66-4396-a962-9dd5aec20aaa)

After:

![Screen Shot 2023-07-12 at 17.41.47](/attachments/65822b16-9ba9-4452-94b1-f8c145ffd78b)

Reviewed-on: https://gitea.com/gitea/gitea-docusaurus/pulls/44
Co-authored-by: HesterG <hestergong@gmail.com>
Co-committed-by: HesterG <hestergong@gmail.com>

docusaurus.config.js

@@ -153,6 +153,7 @@ const config = {
           alt: 'Gitea Logo',
           src: 'img/gitea.svg',
           href: 'https://about.gitea.com/',
+          target: '_self',
         },
         items: [
           {
@@ -172,6 +173,7 @@ const config = {
             label: 'Blog',
             href: 'https://blog.gitea.com',
             className: 'internal-href',
+            target: '_self',
           },
           {
             type: 'custom-apiDropdown',
@@ -212,6 +214,7 @@ const config = {
             label: 'Sign In', 
             position: 'right',
             className: 'internal-href signin-button',
+            target: '_self',
           },
         ],
       },

i18n/zh-cn/docusaurus-theme-classic/navbar.json

@@ -10,5 +10,8 @@
   },
   "item.label.Support": {
     "message": "支持"
+  },
+  "item.label.Blog": {
+    "message": "博客"
   }
 }