clarify aspects of the dump command (#26887)

clarify aspects of the dump command

Possibly closes #26862

---------

Co-authored-by: delvh <dev.lh@web.de>

cmd/dump.go

@@ -128,7 +128,7 @@ It can be used for backup and capture Gitea server image to send to maintainer`,
 		&cli.StringFlag{
 			Name:    "database",
 			Aliases: []string{"d"},
-			Usage:   "Specify the database SQL syntax",
+			Usage:   "Specify the database SQL syntax: sqlite3, mysql, mssql, postgres",
 		},
 		&cli.BoolFlag{
 			Name:    "skip-repository",

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

@@ -334,9 +334,9 @@ in the current directory.
   - `--skip-attachment-data`: Skip dumping of attachment data. Optional.
   - `--skip-package-data`: Skip dumping of package data. Optional.
   - `--skip-log`: Skip dumping of log data. Optional.
-  - `--database`, `-d`: Specify the database SQL syntax. Optional.
+  - `--database`, `-d`: Specify the database SQL syntax. Optional (supported arguments: sqlite3, mysql, mssql, postgres).
   - `--verbose`, `-V`: If provided, shows additional details. Optional.
-  - `--type`: Set the dump output format. Optional. (default: zip)
+  - `--type`: Set the dump output format. Optional. (formats: zip, tar, tar.sz, tar.gz, tar.xz, tar.bz2, tar.br, tar.lz4, tar.zst default: zip).
 - Examples:
   - `gitea dump`
   - `gitea dump --verbose`