contents(rpmfusion): add sed command and some other fixes

- Put RHEL 8/9 before 7/6
- Remove instruction of using su -c 'CMD'
- Add sed command
- Make it clear that it only has Fedora example
- 请参考 -> 可参考

contents/rpmfusion.mdx

@@ -32,10 +32,10 @@ cname: 'rpmfusion'
     {
       title: '发行版',
       items: [
-        ['CentOS/RHEL 7', { version: '7' }],
-        ['CentOS/RHEL 6', { version: '6' }],
         ['CentOS/RHEL 8', { version: '8' }],
         ['CentOS/RHEL 9', { version: '9' }],
+        ['CentOS/RHEL 7', { version: '7' }],
+        ['CentOS/RHEL 6', { version: '6' }],
       ]
     },
   ]}
@@ -47,54 +47,61 @@ cname: 'rpmfusion'
 
 </CodeBlock>
 
-注意：没有将当前用户设为管理员的用户，需要将 `sudo CMD` 替换为 `su -c 'CMD'`，并输入 root 密码。
-
 ### 修改链接指向镜像站
 
-安装成功后，修改 `/etc/yum.repos.d/` 目录下以 `rpmfusion` 开头，以 `.repo` 结尾的文件。具体而言，需要将文件中的 `baseurl=` 开头的行等号后面链接中的 `http://download1.rpmfusion.org/` 替换为
+安装成功后，使用以下命令修改 `/etc/yum.repos.d/` 目录下以 `rpmfusion` 开头，以 `.repo` 结尾的文件：
 
 <CodeBlock>
-
-```
-{{http_protocol}}{{mirror}}/
+```shell
+{{sudo}}sed -e 's!^metalink=!#metalink=!g' \
+         -e 's!^mirrorlist=!#mirrorlist=!g' \
+         -e 's!^#baseurl=!baseurl=!g' \
+         -e 's!https\?://download1\.rpmfusion\.org/!{{http_protocol}}{{mirror}}/!g' \
+         -i.bak /etc/yum.repos.d/rpmfusion*.repo
 ```
-
 </CodeBlock>
 
-替换后的文件类似如下：
+以 Fedora 下的 `/etc/yum.repos.d/rpmfusion-free.repo` 为例，替换后的文件类似如下：
 
 <CodeBlock>
 
 ```ini
 [rpmfusion-free]
 name=RPM Fusion for Fedora $releasever - Free
-baseurl={{http_protocol}}{{mirror}}/free/fedora/releases/$releasever/Everything/$basearch/os/
-mirrorlist=http://mirrors.rpmfusion.org/mirrorlist?repo=free-fedora-$releasever&arch=$basearch
+baseurl=https://mirrors.ustc.edu.cn/rpmfusion/free/fedora/releases/$releasever/Everything/$basearch/os/
+#metalink=https://mirrors.rpmfusion.org/metalink?repo=free-fedora-$releasever&arch=$basearch
 enabled=1
-metadata_expire=7d
+metadata_expire=14d
+type=rpm-md
 gpgcheck=1
-gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmfusion-free-fedora-$releasever-$basearch
+repo_gpgcheck=0
+gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmfusion-free-fedora-$releasever
 
 [rpmfusion-free-debuginfo]
 name=RPM Fusion for Fedora $releasever - Free - Debug
-mirrorlist=http://mirrors.rpmfusion.org/mirrorlist?repo=free-fedora-debug-$releasever&arch=$basearch
+baseurl=https://mirrors.ustc.edu.cn/rpmfusion/free/fedora/releases/$releasever/Everything/$basearch/debug/
+#metalink=https://mirrors.rpmfusion.org/metalink?repo=free-fedora-debug-$releasever&arch=$basearch
 enabled=0
 metadata_expire=7d
+type=rpm-md
 gpgcheck=1
-gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmfusion-free-fedora-$releasever-$basearch
+repo_gpgcheck=0
+gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmfusion-free-fedora-$releasever
 
 [rpmfusion-free-source]
 name=RPM Fusion for Fedora $releasever - Free - Source
-baseurl={{http_protocol}}{{mirror}}/free/fedora/releases/$releasever/Everything/source/SRPMS/
-mirrorlist=http://mirrors.rpmfusion.org/mirrorlist?repo=free-fedora-source-$releasever&arch=$basearch
+baseurl=https://mirrors.ustc.edu.cn/rpmfusion/free/fedora/releases/$releasever/Everything/source/SRPMS/
+#metalink=https://mirrors.rpmfusion.org/metalink?repo=free-fedora-source-$releasever&arch=$basearch
 enabled=0
 metadata_expire=7d
+type=rpm-md
 gpgcheck=1
-gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmfusion-free-fedora-$releasever-$basearch
+repo_gpgcheck=0
+gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmfusion-free-fedora-$releasever
 ```
 
 </CodeBlock>
 
 ### 更多
 
-RHEL/CentOS 用户请参考 [RPMFusion 官方指南](http://rpmfusion.org/Configuration)。
+RHEL/CentOS 用户可参考 [RPMFusion 官方指南](http://rpmfusion.org/Configuration)。