Remove unnecessary prefix usage (go-gitea#24888)

Since now all articles have a class, the `Usage:` is unnecessary. This
PR will remove them.

Author: lunny

docs/content/doc/administration/backup-and-restore.en-us.md

@@ -1,6 +1,6 @@
 ---
 date: "2017-01-01T16:00:00+02:00"
-title: "Usage: Backup and Restore"
+title: "Backup and Restore"
 slug: "backup-and-restore"
 weight: 11
 toc: false

docs/content/doc/administration/backup-and-restore.zh-cn.md

@@ -1,6 +1,6 @@
 ---
 date: "2018-06-06T09:33:00+08:00"
-title: "使用：备份与恢复"
+title: "备份与恢复"
 slug: "backup-and-restore"
 weight: 11
 toc: false

docs/content/doc/administration/command-line.en-us.md

@@ -1,6 +1,6 @@
 ---
 date: "2017-01-01T16:00:00+02:00"
-title: "Usage: Command Line"
+title: "Command Line"
 slug: "command-line"
 weight: 1
 toc: false

docs/content/doc/administration/email-setup.en-us.md

@@ -1,6 +1,6 @@
 ---
 date: "2019-10-15T10:10:00+05:00"
-title: "Usage: Email setup"
+title: "Email setup"
 slug: "email-setup"
 weight: 12
 toc: false

docs/content/doc/administration/fail2ban-setup.en-us.md

@@ -1,6 +1,6 @@
 ---
 date: "2018-05-11T11:00:00+02:00"
-title: "Usage: Setup fail2ban"
+title: "Setup fail2ban"
 slug: "fail2ban-setup"
 weight: 16
 toc: false

docs/content/doc/administration/git-lfs-support.en-us.md

@@ -1,6 +1,6 @@
 ---
 date: "2019-10-06T08:00:00+05:00"
-title: "Usage: Git LFS setup"
+title: "Git LFS setup"
 slug: "git-lfs-setup"
 weight: 12
 toc: false

docs/content/doc/administration/https-support.en-us.md

@@ -1,6 +1,6 @@
 ---
 date: "2018-06-02T11:00:00+02:00"
-title: "Usage: HTTPS setup"
+title: "HTTPS setup"
 slug: "https-setup"
 weight: 12
 toc: false

docs/content/doc/administration/logging-documentation.en-us.md

@@ -1,6 +1,6 @@
 ---
 date: "2019-04-02T17:06:00+01:00"
-title: "Advanced: Logging Configuration"
+title: "Logging Configuration"
 slug: "logging-configuration"
 weight: 40
 toc: false

docs/content/doc/administration/reverse-proxies.en-us.md

@@ -1,6 +1,6 @@
 ---
 date: "2018-05-22T11:00:00+00:00"
-title: "Usage: Reverse Proxies"
+title: "Reverse Proxies"
 slug: "reverse-proxies"
 weight: 16
 toc: false

docs/content/doc/administration/reverse-proxies.zh-cn.md

@@ -1,6 +1,6 @@
 ---
 date: "2018-05-22T11:00:00+00:00"
-title: "使用：反向代理"
+title: "反向代理"
 slug: "reverse-proxies"
 weight: 16
 toc: false